Diablo III: Reaper of Souls

After trying several builds with Marauder
Meticulous Bolts Ball Lightning is iffy. Doesn't feel as powerful as other builds. The long amount of time you have to stand still to create a line to hit things is questionable. It feels less safe because of the travel time now.
Immolation + Arsenal: Tried this one first actually. Immolation is still super high proc rate, so with Mortal Enemy, you can keep your Hatred up, even without a Kridershot, and then spam Arsenal for the deeps. Acceptably good at higher difficulties, even if you don't have a Kridershot, but this is a very poor choice on things that die too quickly, i.e. Mortal Enemy is never up.
Frost-Fire: Your Sentry fires three rockets. Highly doubt this is intended. Since the rockets each do 120%, it's an additional 360%, or 720% with Ballistics per attack. Though they're not affected by any of the other Marauder effects. A Frost Arrow with 5 Sentries should be doing 330 * 3.0 * 2.0 = 1980% + 720% = 2700%, which is a 36% increase in damage. Arsenal is extremely good as with the other build and rockets rekt things very well.

As a reference, the damage difference between having a Kridershot and not having a Kridershot at 2.00 APS using only Elemental Arrow/Entangling Shot (300%/200%) and Custom Engineering is 1.76x more damage.

By using Seething Spines, you can have a different weapon than Kridershot and use Chakram as your generator. The downside is the loss of 2 extra sentries, and their damage bonus. So that's 5/3 of your damage output, plus 300%/220% of the damage bonus, or 2.5x weaker. The only alternative weapon worth using is probably Calamity. Serpentine does fairly high damage, so the compensation would be 1.51 from that plus 1.2 from Calamity = 1.81, which doesn't make up the difference, not to mention fewer Arsenals.