Are Controllers too similar to Dominators?

Doms play like low damage blasters/blapper

Controllers play by usuing either strength of locking down a spawn(s) or in AV cases relying on thier secondary, which Doms get the double shaft of PTOD and sometimes insanely high RES

So yes they are exactly the same.

In short, you can build a Controller to have much the same capabilities of a Dominator, but you have to make some specific power choices to do that. The same goes for Blasters, although not to the same extent. Still, the Dominator is the specialist, it has a very specific playstyle. The Controller and Blaster are generic, on the average they have a great deal more flexibility and more choices in how they can be designed and played. They can come close to a Dominator, but never quite match it.

The best way to make a Controller like a Dominator is to take a lot of melee attacks from the Pool, and then once you hit 41 take ranged attacks from your Epic. That will give you the mix of melee and ranged that define Dominators. If you're style is to close to melee a lot on your Dom, the strategy should be familiar to you, a lot of Controllers call it "Scraptrollering".

You will definately want /Kin or /Rad as your Secondary, so you can boost the damage of your attacks, but Containment should do 90% of getting your damage to Dominator levels. You'll never do quite as much damage with only Power Pool attacks, but you'll also be debuffing your foes' damage or to hit, and healing yourself, which will make you much more resiliant than a Dom. You won't be able to take your full Secondary if you concentrate a lot on Pool attacks, but since Rad and Kin both boost both offense and defense with the same powers, it should be obvious which ones will be the priorities. Do pick up a couple of team support powers so your allies don't complain, though.

The Blaster, as mentioned, will do more damage, but will have less AoE control, and will be just as fragile defensively. I'll just repeat what was said above, which is that you want either /Energy, /Ice, or /Psi for your secondary. You also want to close into melee and use the "Blapper" strategy, not just because that's closest to what the Dom does, but also because you need to close to melee to use your single target holds/stuns.

While /Devices does have some fine controls (mainly stealth, although most people don't consider that control) I don't think it actually matches the Dom style because it has no melee attacks. Instead you have your mines you can plant to lure your foes into. It's not really a Dom-like strategy, although it is just as effective in its own right.