Let mission agent NPC offers several options (three?) when accepting the mission, so players could choice them based on specialization.
Marauder pilot will skip burner missions and vice versa.
Also, developers will acquire unique statistics on which missions are taken most often and which - most rare. This will highlight missions with problematic design (no one wants them 
), so they (devs) will know what to fix (if needed).
Would basically circumvent the penalty for declining once every 4 hours and allowing people to cherrypick the most lucrative missions only. Leading do even higher max income in ISK/h. Since the profits for L4 are already very good if you know how to run them efficiently, I am not so sure that even more ISK in the game would be a good thing.
There is absolutely no reason that this should not be an option.
The difference between incomes in level 4 missions is not so drastic that this is going to make a dent in the economy whatsoever, but it will keep players from getting the dreaded chain of standing destroying missions. Everybody wins, quality of life only goes up.
I wouldnât mind rewarding effective agent standing 5 with a second choice and rewarding effective agent standing 9 with a third choice
First off, check @Aceyfacey 's explanation how heâs managing to decline missions he doensât like :
He doesnât mention it, but you can also run epic arcs to bolster your faction standings w/o taking negative impacts towards the other factions.
Also, NPC agents usually cluster in pockets, i.e. other NPCs of the same faction will be closeby. If one Agent gives you a poor mission, and your deny cooldown is active, travel to the next one. The Isenairos Pocket (i.e. Solar Systems around Isenairos), for example. has many lvl4 security agents of corporations that are part of the Caldari faction, all within 2 jumps of each other, making it a popular missioning area.
Missioners playing eve the right way, use so called mission pullers: You put multiple alt capsuleers into your missioning stage station, and instead of attempting to go to another station and check whether the NPCs there give you better missions, you alt-tab to the next client, and check whether the other alt can get a better mission. If it can, the alt capsuleer âpullsâ the mission, and the main runs it.
In most situations, you want to create a fleet consisting of your mission runner and the puller alt(s), which will cause the agent and corporation standings gains, as well as the corporation LP, to be shared among both, which is handy in case your pullers lack standings with some corporation, in which case you can powerlevel your puller with the runner. If the puller denies a mission, only the puller will suffer a standings hit, while the standings gain will be shared among the puller(s) and the runner(s). Faction standing gains are never shared, with the exception of the epic arc final mission rewards.
Of cause, the two techniques can be combined, in case the puller gets poor missions, too, and alt tabbing to other pullers yields only in more poor mission provisions until you find our you werenât playing eve in a sufficiently good way, i.e. you ran out of alts before you ran out of poor mission offers.
This is nice.
Make an isk form missions in the game itâs fine it doesnât hurt anybody , the Plex is the one that kills the game economy
Yes, THIS word - cherrypick.
If player has to cherrypick that means we have poorly designed, unbalanced missions which SHOULD BE fixed.
Also, about concern of increased ISK flood - I believe, itâs only relates with âpureâ ISKs, like NPC bounties and mission rewards. But we also have commodities (tags, loot, salvage) and Loyalty Points (which has a decent ISK-sink potential). So, it doesnât look that bad to me 
PLEX trade doesnât create ISK though, the ISK/PLEX only changes itâs owner. In fact it, PLEX trade removes ISK from the game, via SCC market transaction taxes and/or contract fees. ISK is created when CONCORD hands players kill bounties, when Mission reward bounties are payed out, and when NPCs buy Overseer Personal Effects, Sleeper Data, Abyss Loot, and other items that are âgeneratedâ.
Arguably, Mission Bounties are the least significant ISK faucet, as for security missions, which pay more bounties then the other mission types, pay considerably less ISK then the concord bounties on the NPCs you had to wreck in order to turn in the mission.
The LP and NPC regular drops might be a source of income for a player, though that income doesnât have an ISK form before other players are willing to trade their ISK for those.
Iâd have run burners if NPCâs didnt cheat. But they do cheat, so I never ran them.
But as they donât incur penalty to decline, I donât the current system of one at a time.
How do they cheat? Repping too hard? :))
Most target ships in the burner sites can be fit by players to be surprisingly powerful if youâre willing to invest into them hard enough. It comes at the odds of losing all those modules though, and while you might not care about it, the one scooping the loot definitely cares. I.e. if those rats dropped blingier loot then they do, it would feel more like wrecking similar player ships.
Hereâs a HAC+combat recon picking a fight with 5 marauders and a 50+ cruiser and BC fleet, showing off what enough bling can do:
A small detail is that he was isk negative, because the whole fleet was less expensive then the HACâs boosters alone.
What happens if you NOS an NPC?
From some you get cap, from others you donât. Depends on how they are programmed. What does it matter anyway, they are far from being unbeatable if you know what to do. In fact, they are pretty easy with a well-prepared ship and there are even guys who specialize in just farming burners and ignore the standard missions.
So youâre saying NPCs are totally unpredicatable? And that it requires specialist information to beat them rather than just knowing what ship they are in? Iâm totally ok with it taking a specific fit to kill them. Iâm not ok with needing each of these fits in each of my mission hubs just to run missions.
its all about the informations ! some activities dont need that much and some activities need a lot of informations !
btw ⌠still a L4 mission ( not a burner ) you are need some specific informations â damage types
nothing ingame tells you how to fit your ship agtainst [insert your favorite pirate faction] and which resistanz holey they have or which dmg type they deal ! the first time you get this informations are in the missions ( or on 3rd party sites ) when you can look at their info and see the information you need
but hey⌠before you start you didnt know that angles fires a lot ecplosive and have a lot of EM/THM resistance and now youre bring your abadon to this mission ⌠wich wonder that this is not a good choice of ship oO
as you see, almost everything needs specific informations ! the fact that after 20 years eve everybody knows that [insert your favorite pirate faction] deals damage type X and needs damage type Y !
badly marauders stop you from needing such informations 
they are to strong for L4 with their tank ability´s and their 2500+dps âŚ
Again, what happens if i NOS an NPC?
and where exactly is your problem with âNOS an NPCâ ?
That sometimes a module does what it is supposed to do, and other times it does not.
you are talking against NPC`s ⌠why you are needing any NOS for any NPC activity ? oO
if you need a NOS then youre fit is â â â â and you need to rework it !
you also dont start to e-war NPC´s with jams or damps xD