RAC5s are fun and effective. We really can have both. The era of every good design needing to be 16 DHS with 2x ERPPC and 6x ERML (or a similar array involving Gauss Rifles) is drawing to a close. Variant armor opens up so much design space in this game, and now the 'best' designs will also be the ones with the most flavor and variety to them. The Shockwave is an excellent example. The Orion 2M and 3M are also very good. The Anzu J70 also falls into the 'at least decently playable' tier; it has significant flaws, but none are outright crippling.
You want Mechs to have meaningful damage output of at least two different types (where the three types are 'energy', 'ballistic', and 'missile'). The Juliano has good to stellar damage in two of the three. The various Inner Sphere Market Mad Cats have two of the three. Even the Carronade marginally qualifies (and its shortcomings in this field are compensated for by the fact it is very good against aerial units), as do our Archer 8M and 9M.
Once Reflective Armor becomes more common on mass production units, along with Blue Shield, we're going to begin thinking of energy boats as 'specialists who need teammates' with good and bad matchups, instead of being optimal. I've said it a lot, and it's going to require more TRO products taking advantage of this before it's our game reality, but I look forward to seeing it happen. Imagine a game where the Hellstar is valuable but not unquestionably best-in-class at its job, because some common enemies take half damage from all its guns. That would be a very good thing.