Spoiler
So, for me it looks like ACs and UACs should be a high DPS weapon with some positional game potential. Mechs equipped with them should generally lose cover-based trades against laser/ppc/gauss specialized mechs, generally win in close quarters encounters (though less brutally compared to SRMs / SPLs / current LBs) and be roughly equal at open ground engagements at less than ~60-100% of AC's optimal range (percentage is less for smaller AC's).
As for UACs... they are currently quite frustrating for the shootist when they jam... and for the target when they don't.
So, the suggestion is (please read till the end
). All exact numbers are "from head" and show just a general idea. It can be implemented in lots of ways i think, and some of them are better than suggested.
1) Bring back the AC and UAC stats from pre-November? patch (i don't remember when exactly cooldown and heat were increased, but it was quite recently). Skill tree further affects cooldowns negatively, so it should be fine.
2) Adjust velocity for all "basic" ACs with focus on AC/5 - for example 950/1050/1150/1800 instead of current 650/900/1150/2000. Clan ACs should have slightly less velocity with more velocity reduction for lighter guns (hello t-comp), say, 925/1000/1075/1650.
3) UACs should get further velocity nerf to justify increased DPS, with Clan lighter UACs sufferting more (hello t-comp), say 800/900/1000/1600 for IS and 700/750/850/1400 for Clan.
4) Most important thing - increase UACs jam chance drastically (by 50% at the very least, with final 74/76/78/80, for example) and reduce jam time drastically with even more reduction for heavier ACs, say, 0.3/0.75/1.0/1.1 . Remove jam chancenodes and bring jam time ones. There nodes reduce jam time by value + percentage, say, 0.04 + 15% of remaining time (and there're 6 nodes in the skill tree). This basically results in ACs having a rather small chance of dealing additional damage instead of constantly dealing additional damage with a chance to break.
5) Reduce velocity benefits from the skill tree to 10% total, and give low-tonnage clan mechs/ompipods UAC velocity quirks to compensate for no t-comp (say, 2 UAC/10 HBR normally doesn't have t-comp at all). Heavy ballistic boats should stay untouched.
So, for me it looks like ACs and UACs should be a high DPS weapon with some positional game potential. Mechs equipped with them should generally lose cover-based trades against laser/ppc/gauss specialized mechs, generally win in close quarters encounters (though less brutally compared to SRMs / SPLs / current LBs) and be roughly equal at open ground engagements at less than ~60-100% of AC's optimal range (percentage is less for smaller AC's).
As for UACs... they are currently quite frustrating for the shootist when they jam... and for the target when they don't.
So, the suggestion is (please read till the end

1) Bring back the AC and UAC stats from pre-November? patch (i don't remember when exactly cooldown and heat were increased, but it was quite recently). Skill tree further affects cooldowns negatively, so it should be fine.
2) Adjust velocity for all "basic" ACs with focus on AC/5 - for example 950/1050/1150/1800 instead of current 650/900/1150/2000. Clan ACs should have slightly less velocity with more velocity reduction for lighter guns (hello t-comp), say, 925/1000/1075/1650.
3) UACs should get further velocity nerf to justify increased DPS, with Clan lighter UACs sufferting more (hello t-comp), say 800/900/1000/1600 for IS and 700/750/850/1400 for Clan.
4) Most important thing - increase UACs jam chance drastically (by 50% at the very least, with final 74/76/78/80, for example) and reduce jam time drastically with even more reduction for heavier ACs, say, 0.3/0.75/1.0/1.1 . Remove jam chancenodes and bring jam time ones. There nodes reduce jam time by value + percentage, say, 0.04 + 15% of remaining time (and there're 6 nodes in the skill tree). This basically results in ACs having a rather small chance of dealing additional damage instead of constantly dealing additional damage with a chance to break.
5) Reduce velocity benefits from the skill tree to 10% total, and give low-tonnage clan mechs/ompipods UAC velocity quirks to compensate for no t-comp (say, 2 UAC/10 HBR normally doesn't have t-comp at all). Heavy ballistic boats should stay untouched.