It definitely depends on how comfortable you are with shields. With all of the arbalest users around nowadays, I can't say brown lion is that reliable anymore unlike how it was in the past. I think shield is more useful than IF up until 4 shield, then IF is better if you can stack it (compared to 5shield it's debatable). Quickly dropping your shield with H and picking up a spare (most likely a 4-difficulty shield) is invaluable when it's highly likely that ranged are the last players left. You're more than capable without shield, so it all depends on how much trouble you feel you're having with ranged currently.
Losing 1PS is like -2 damage on your weapon. If you feel that's okay, it's a good change (+you get easier hits and more speed bonus). With 6PS, I mostly target lightly armored or give assists against heavily armored opponents. Damage output against heavily armored ganks is difficult since they'll just tank your hits, but on the flipside you're fast enough to just kite.