Chimaera is still solid. But if executrix is at higher star level, chimaera might not be the best option
My chimaera is 5 stars and exec is 7 stars, the 4th reinforcement used be of no value but now it does matter.
Also i always lose against a strong 7 star chimaera fleet, when i use my 5 star chimaera (thrawn is maxed out tho). Reason being, simply my chimaera is slower than opponent's and I get wiped out by his ult, no matter how well i've managed the game till the point. Kinda makes me piissed off really.
However when i use 7 star exec, i can win at least sometimes, i havent figured out the reason quite yet, but i think it's because i'm more likely to call more reinforcement before enemy's ult comes compared to when i use a 5 star chimaera, due to faster capital shop speed (166speed) and 1 more slot. (3 vs 4) More reinforcements deployed before enemy ult = Higher chances to survive afterwards and get a chance to use my ult.
One drawback tho, is that exec ult has been severely nerfed. Now I do have to pray on rng if i want to kill just 3 ships with ult.