If you ask me, with all new buffs you don't really need any dot/stacking or ramping up gems for tx or less than tier 60 difficulty. So get the BotP or esoteric gem. You might also drop F+R set for Endless Walk. The top end gear is not really required for mid-end farming. Prioritize survival and mobility.
dps is not necessarily an issue nor priority below tier 65 difficulty. Endless Walk is primarily suggested for its toughness feature. Plus it totally removes the need for a generator. Btw Marauder setup is the least mobile of all DH builds with the help of sentries, pets, etc.
Endless walk can be tricky though, since we are a mobile class and we cannot stand still that much.
M6 has the least movement of the 4 sets due to its HUGE defensive boost with Zoey's (That shit is INSANE) so there is no need to avoid melee, or, well, anything really. Also, the damage portion of Endless Walk gets boosted VERY quickly, takes like 3 seconds to go from 50% damage reduction to 100% damage addition.
It also frees up your ring slot which is pretty powerful now, with things such as Unity, the improved Oculus ring (which makes up for the damage loss from Focus and Restraint compared to Endless Walk), Convention of the Elements (if not already cubed), or even Ring of Royal Granduer (Can be used to have both Garwolf and Visage for huge damage reduction in groups)