I’ve pretty much played every mastery and build to some extent, I would say Marksman and Sorcerer have been the most lacking. However, Sorcerer just lacks some oomph and has to compete with two very strong masteries; Runemaster and Spellblade. Marksman, however, is just a mess.
First and foremost, Marksman needs baseline access to additional projectiles and pierce/chaining. I would say that Marksman mastery bonus of 50% increased damage, which is rather underwhelming, should be baked into the abilities, and then replaced by a passive that grants 1 projectile per X dex, 1 pierce per X strength, or 1 chain per X int with pierce overriding the ability to chain, capping at 2 or 3.
Detonating Arrow has decent scaling, but its arming time makes it feel rather awful to clear with, and most viable builds use it as an extension of traps. Its arming time should be removed, with a passive readding the arming time and increasing the damage done per arrow that hits the target during that period, giving it synergy with fast hitting single target abilities like Flurry.
Multishot has a decent skill tree but its scaling is complete ass, and it’s rather boring mechanically and visually. I would say the 35% more damage from Heavy Arrows needs to be baked into its scaling, with it and Toxic Gift being made into passives that give a chance for Multishots to be replaced by fire and lightning arrows that receive further scaling from passives like Fire and Steel.
Dark Quiver is currently one of the most useless and ill designed abilities in the game, but would be perfectly fine as a passive aura with buffed arrows generated over time, with its numbers tuned as a result. It could grant primarily physical/void/poison scaling baseline, improved and converted by the elemental arrow passives in the passive tree if the player wishes.
Hail of Arrows is ok, but its passives have too many draw backs in terms of duration and delay. It doesn’t feel good when almost every level of the ability also comes with some kind of draw back, but that could be said about most abilities in LE (which is probably my biggest complaint about the game).
Cinder Strike, when used by a bow, could have additional projectiles count as second/third attacks instead via the Overexertion passive. So with enough projectiles, a Marksman would shoot a first attack projectile in the center, with additional projectiles off to the side acting as the second/third attack. Cinder Strike has a lot of potential to be a fun fire bow build, but that 30 mana cost is nasty, and then slurps up another 5 passive points to be moderately efficient. That node should be reduced to 2 or 3 points while still remaining at a value of 60% or even more.
Flurry should be usable while moving at a penalty, have slight tracking, and have the ability to instead fire other specialized shots to improve its synergy and make it more visually appealing.
In the end, most bow abilities in this game feel like they require a ton of passives to even be usable and then still lack scaling or utility in the end. The power and synergy between abilities, compared to a mastery like Warlock, is just insane. Explosive Trap is the only ability with real potential and it technically doesn’t even belong to Marksman nor is it a bow ability.