This is literally the dumbest thing I have ever done. TheWatchman's CTF-1X "Steel Rhino" does the same thing except better in every way. But hey, it's an AC/20 Catapult. At least that's something, right?
So this build is a K2 with one AC/20 and four MPLas and your propositions are a boomjag and a AC/20+PPC phract - in other words two mechs with almost no connection and built on different chassis... this is not constructive. As for the superiority of the CTF-3D alternative (JJ mostly), well, it's acknowledged in the name of the build.
I'm just the fact that K2 and AC/20 incompatible. Neither speed nor agility. AC/20 to have more suitable chassis. K2 is almost ideal for such an option: But the topic is not about that of course. I beg your pardon. I hope you get the idea that I wanted you to hear.
If you want my personal opinion about this, since I always use an XL engine on my Catapults and like to use the vertical mobility of the arm, I don't like AC/20 on the K2. But there are plenty of very powerful builds using this weapon (with very valid reasons), way enough to make me think K2 and AC/20 are perfectly compatible.
Because the build is too "short-handed". At Alpine Peaks will tangible problems. Even in this embodiment: 2xAC/10 in my opinion is better.
I was so used of you posting totally unrelated builds it took me twice to realize this one was actually an alternative to the OP build. I agree with you on both points: - even after the buff, MPLas don't worth the weight, imho. I prefer standard MLas and four free tons; - double AC/10 is better than a single AC/20, giving you better range and DPS without losing on manoeuvrability since you can mount an XL engine.