I normally play casters but decided to try out ranged and this inquisitive thing because a ton of people whine it is super over powered. It seems really slow.
Compared to any decent DPS caster, ranged weapons in general are gonna feel weak in heroics. That's simply the nature of DDO's current power (im)balance. At least you aren't trying to level a thrower!
That said, repeaters and dual crossbows were
rebalanced last year. The tl;dr summary is SSG reduced their attack speed but removed the Doubleshot penalties; so they're worse for heroic leveling than they used to be, but better in Legendaries. You'll probably see a bunch of Artificer 4-based Inquisitives going for Inquisitive capstone + T4 Battle Engineer.
The other major change last year was the addition of
AoE attacks. Here's where pure rogues missed out, as there's no AoEs in the Mechanic tree - unless you count traps which have never scaled well and are badly in need of either buffs or replacement IMO - hence why hardly anyone plays pure Mechanics anymore.
Would it be better to go to an arcane archer ranger?
For better or worse, SSG has always tried to pigeon-hole archery into the "low rate of fire / high damage per shot" category, with varying degrees of success. One advantage to ranged ranger is access to more AoE attacks; a pure ranger with 42 Deepwood Stalker / 23 Horizon Walker / 7 Arcane Archer has 4 AoEs, with enough points left to grab Haste Boost (still Best Boost 99.9% of the time) from Tempest or Vistani.
That said, it's still gonna feel hella low-n-slow compared to pure casters. I feel like leveling a ranged toon these days is a test of patience more than anything else.