I have had good luck with the tom thumb. Everyone hates me for that, but it's true. I find that if I ride in an Argentine Snaffle everyone magically thinks it's a good bit even though it's nearly the same as the tom thumb. Maybe get yourself an Argentine Snaffle and don't worry about what other people think.
Of course I mainly neck rein and have soft hands. And maybe there are better bits out there. I am sure a lot of harsh handed people use a tom thumb and they shouldn't be. There are a lot of harsh handed people period.
But if your horse goes well it in, I really don't see an issue. Especially because you are concerned about it. The people who are really heavy handed don't even know they have a problem. They just think they are right.
These are some other bits I like. You might want to try just a simple curb like this one on the top left, with short leverage: C Bits and Cutter Bits
And some others: AT Low Port Loose Cheek Low Port Western Bit 5in - Horse.com NP Sweet Iron Loose Cheek Western Curb Bit 5in - Horse.com
Mylers are pricey, but my Missouri Fox Trotter loves this one: Myler Flat Shank #89-11335 Myler Bits (Equine - Supplies Tack - Bits - Working)
I originally got one without a port, but both of my horses prefer the one with the port.
Anyway, let the horse be the judge. Only you know how well your horse goes in your current bit or any other you might try.