| Ivanatorinnit |
The only limiting factor in building a ship is your size and BP. Shields are probably, IMHO, the most BP efficient way of mitigating damage due to the fact that they:
A. Regenerate over time and in combat (so no UBP cost to repair during downtime).
B. Don't let critical effects through unless they're breached and
C. Aren't particularly bothered by the NPC gunners being literal Munchkins (They're gonna hit at some point regardless of your ships AC/TL investment so why not have more 'health'?).
Compared to AC/TL:
A. If you get hit you get hurt (and therefore need to repair the ship out of your own pocket).
B. If you get crit/take enough damage the negatives to your rolls can place you in everybody's favourite "death spiral" situation which sucks when
C. You probably(definitely) are going to get hit(eventually at least).
Shields are even better when you realise you don't even have to have 90 in each quadrant. I believe the minimum you can leave per quad is 10% of the current shields? So with a little luck you can start every combat with the enemies staring down a huge 144 front, 90 sides and 36 rear that the science officer can adjust before every gunning phase.
The problem is that most of the ships provided by the modules and books seem to be built in a 'Balanced' way e.g: weapons in multiple arcs, variety of defenses, plenty of none combat stuff like medical bays, SECs ETC. When your players spend all of their BP on the comparatively cheap (vs AC/TL investment) HUEG shields with one HUEG linked turret weapon (or front arc weapon with enough engines+pilot skill to always face the enemy) they're probably gonna faceroll most encounters.
Sources: My anecdotal experience as a (slightly) power-gaming player whom enjoys building ships with big shields and big gun.