The T3Ds are still going to have better fittings and plenty of options, plus the option to situationally outclass the AFs, so they should still be able to win it’ll just take more skill to make a T3D shine than an AF.
As for the T2 dessies that’s a non-issue. Interdictors and Command Destroyers are specialized ships with unique bonuses and roles that other ships flatly can’t replicate. Their raw combat potential is pretty much secondary.
Plus stuff like solo Thrashers will still have the things that make them fun and unique because they’re not actually losing anything here, and a change like that shouldn’t put AFs actually above where T3Ds are now.
AFs and HACs are both holdovers from the pre-tiericide when some T2 ships were basically just “T1 but better”. Back then Destroyers were just bad and both hull types had a pretty unique role. Then Eve moved on.
CCP have tried to preserve the gameplay around them as best they can, and people clearly want that gameplay or there wouldn’t be so many calls to do something more with the ships. I just don’t think OP’s suggestion is particularly good. It, like so many other AF rework suggestions, seems to be trying too hard to be novel and hasn’t really considered the balance implications of the actual suggestion.
Letting AFs fit Grapplers would make them OP against other small ships, because the big disadvantage to Grapplers is that they’re mounted on big slow battleships that everything else can keep range from. Giving them Heavy Scrams and Points would make them the ultimate anti-cap tackle because no cap short of a Carrier, and then only maybe, is going to be able to peel off a properly tanked AF.
Web immunity would be ridiculously OP though, because if you’re immune to webs you can keep transversal where your enemy can’t, and in a frigate duel you can pretty much disengage at will.