Whether it makes sense or not, the Sova carrier already boosts production...my problem with simply adding 12 more combat abilities is that odds are they won't be all that unique...not that civilian bonuses are unique, but capital ships in general don't grant such bonuses and you can't place envoy bonuses on your own planets, so it would certainly serve a purpose...
Given the current entity modifiers, etc. that are in the game, additional abilities are simply going to be reusing the same bonuses already given by existing abilities...sure, you can get unique combinations (an AoE ability that regenerates hull and shields) or turn single target abilities into AoE (a debuff that reduces many targets' armor instead of just one), but we are still looking at the same bonuses/penalties...
To truly have new abilities, either 1) they are going to have to make new types of entity modifiers, etc. or 2) they are going to really have to think outside the box...
For example, you could have a time dilation field ability that reduces the linear/angular speed, weapon/ability cooldown, build/construction rate, and passive regeneration of all ships and structures that mimics a slowing down of time...or, you could have a singularity inducer that spawns a black hole on a targeted ship (think opposite of repulsion)...or, you could have an ion pulse that is an AoE ability interrupt...
The problem is, crazier ideas can be harder to balance or actually make useful...not impossible, but it really depends on what priorities the design team has, and good cap abilities may or may not be one of those priorities...