This is probably the best implimentation of the drop dash in SRB2 I've ever seen, but I have 2 things I want to bring up in regards to this mod, one is an issue I found in it's functionality and the other is a minor option that I think many people would appreciate.
First of all, I noticed that when this mod is turned on the roll jump lock is disabled, while that may be a personal preference for alot of people, given the fact that most people these says use the "Many minor tweaks" mod which has an option to turn that off by default, I see no reason as to why it needs to be in here, especially since it disallows people who prefer to use this mod with the roll jump lock on.
The second is that I think that having an option for using the drop dash with the JUMP button instead of the SPIN button would be a nice option, either as a toggle or as a separate download option (it's up to you in that regard).
While it does mean that the Thok would be removed, I think it's a good option for those who may prefer to only play as Sonic with the Drop Dash only.
But with that said, this mod shows great potential, I love how the drop dash in and of itself has been implemented, I can't think of a single way to make the move better, I genuinely think that if you just make the additions I stated above, it could be even better.
You did a great job with this, I hope to see more from you in the future!