I suppose you are using that ship for PvE, not for PvP. I doubt you can find any other drone boat, that would offer you same gameplay.
There are 4 battle ships with bonuses for drones out there (apart from Dominix itself). But since they all lack the unique drone range bonus Dominix have, you will have to relay on guns / missiles as your sniper damage dealer. With Dominix there is no problem to get drone damage optimal beyond 100 km for all sentry drones (except garde). You can get optimal for wardens on any other battlehips somewhere between 80-90 km but that will cost you lot of slots… So it make sense, IMHO, to keep you drones shooting targets, that are closer, than 70 km from you. So you have two choices: you go semi-brawle, with working range between 50-70 km from NPC or you still LMJD 100 + km from them and have missiles (guns will not have optimal to shoot that far with any reasonable ammunition type) working on larger / slower trargets while you sentries aniihilate all small and quick targets, burning toward you with 0 transversal. Only Rattlesnake and Armageddon can fit launchers. But Armageddon does not have any related bonuses.
So - yes, it is still Rattlesnake. RHML or cruise missile launcher is a subject of discussion, because you can get over 100 km even with RHML. But you will find very soon, that using sentries to finish targets almost killed by your missiles is much more effective, than use launchers to do all the job… Which will force you to use Rattlesnake in 60-70 km range from NPC any whay.
And in that range you can use Dominix Navy Issue or Nestor to apply about 1000 DPS of instant damage at 50-80 km range. Tachyon fited Nestor offer a little but more range, 425 mm Rail Dominix - slightly more damage… But both will lack tank, required to sit still next to you drones.
After all those troubles you will most probably come to what most mission runners use now:
Rattlesnake for whole room clear
Machariel for brawler mission blitz
Cheap sniper fit Dominix for missions in low sec
Some players use maraduers, but that solution is ISK/skill intense, so it is a different story.