Fencer skills on your build is almost the same as mine. The only difference is I got lvl 10 on Sept to get lvl 1 on Esquive since it looks fancy and make petals fly around. 
Get bash 3 so you can knockdown and group up mobs(or get lvl 3 bash,learn knockdown attribute, reset skill, get lvl 1 bash, keep the attribute)
Two-handed Sword Mastery:
No. I have a guildmate, he has higher str than dex and the difference in our crit attack stat is not even 50%, even though I have higher dex.
Gung ho vs Concentrate:
If you start hitting 100k per hit on composee, Concentrate will become worthless and Gung Ho will give you more damage since Gung ho gets multiplied by skill multiplier, even by crit. I have 140 str, 170 dex invested and I didn’t even get concentrate.
Lastly, those people who don’t even invest in crit gears and whine how epee garde is so weak should give their rapier and fencer costume back to Sorsha Hutton 