Not much left to add here, I see, but I'd still like to try:
I think that, no matter what type of game you play, you pick one master trait to aim for. On very rare occasions (due to finding some exotic special weapon or some such) you'll want to divert from that path, but otherwise these masters have enough to add to build towards these in a fairly straight line.
Since master traits also exclude the availability of certain skills, and you know you'll only have so many points to spend, eventually, you can more or less plan out the entire course beforehand. To use the Cateye example, I'd take INT-INT-SOB-SOB-TH-MCe, since INT2 provides a huge advantage early on, benefits extra from the extended range MCe brings and you'll need at least 5 other skills before you can take MCe anyhow (or is this outdated?).
For MVm I'd prefer BRU-BRU-BER-BAD-BAD-MVm; again 6 skill required, you'll want BER a.s.a.p. and the extra level BAD allows you to immediately start boosting your health up to 200% once you get MVm.
With this in mind, you can also make a mental shopping list regarding what weapons you'll want to take. For pistols, SOG is a must (as I believe is a master trait), so anything that excludes the use of this will generally be a bad idea. Melee is worthless without BRU, so builds that exclude this tend to rely on another backup weapon.
So, barring any restrictions placed by challenge mode or badge hunting, you base a primary weapon on your master trait - possibly a secondary too - and pick another as backup. Shotguns are versatile enough to support almost anything, rocket launchers can work miracles as well, as long as you manage to keep out of the blast (and not blow up useful stuff in the process). BFGs are a mixed blessing, but I tend to keep one handy as well.