You can get all the extra you need for boating with only 25 points into firepower. From here, the ideal layout I found is 20 survival (everything but AMS nodes), 25 mobility (mostly everything but speed tweak), 20 operations (cut speed retention and improved gyros where you can), and 1 in auxiliary for the extra slot.
The end result is your familiar 2LPL + 2-3-4ML clan mech running with better weapon stats and a lot more tankiness than before, at the expense of 6KPH, that they hardly needed to begin with, giving you a more powerful package than the ones that used to rule the meta for so long.
Mixed builds are penalized as every extra node spent in firepower will cut either tankiness or mobility, so you are left with either strictly laser or dakka boats being the most "well-rounded" mechs, which I believe was the exact opposite of PGI intentions.
Furthermore, IS mechs are all handicapped from the get-go, speed tweak requiring way too many nodes to spec into, with most clan mechs having / being able to equip engines big enough for this not to be an issue.
To sum it up, if you want to min-max your stable (I sure do), the PTS tree system is a step backwards compared to the current state of the game, killing the little variety left on live server, even if it's dictated by the quirks itself.
Edited by Phra, 04 March 2017 - 09:58 AM.