It all depends what kind of build you are aiming for.
Dflight - I can say 99% of the time, maxing this skill is not neccessary. The main purpose of Dflighting is to get close to those range and caster type of character.
Lightning Sentry - If you are a lightning trapper, maxing this skill is a must. Otherwise, putting 1 point in here for death sentry pre req will be enough.
Wake of Fire - I play my melee assassin and I am happy with putting 1 point in here. The main purpose of laying this trap is to lock up your opponent, so you can Dflight in and get a good hit. Maxing this skill doesn't really give you a massive damage boost anyway, leave it in 1 point.
Claw Mastery - If you use claws, max this. More damage, higher percentage for critical strike, nuff said.
TS is useless in pvp nowadays, and so is 20 points spent in one trap. The only useful MA skills for pvp are DTalon, DC and DFlight. WoF might do enough dmg with all synergys maxed if you are a good player who can utilize mb or get the player in block lock when you dtalon them.