*sigh*
I am going to start off with saying that before 3.0 my playstyle revolved around the nikita, more so than any player I have EVER seen.
Now, I am going to talk about edgeguards. The nikita was unarguably an amazing tool for this. But, its not like snake cant survive without it. Pretty much every aerial snake has can be used as edguards, especially his fair and nair. Try them out. They just take appropriate timing and usage. (Edguard is the only part of nikita i miss btw)
Kill potential: the nikita was also really nice as a killing option. However, try his fair, dair, uair, and especially his sticky. If used correctly, all these could be used to annhialate opponents. Stickying and then building up percentage, then utilt or throw into mine after which detonating have better kill potential that the nikita ever did.
Onto the tranq itself
The tranq is not noob friendly AT ALL. It takes time to get used to it, but once you do u will realize that its not bad at all. It supports stickying opponents, which again, undirectly provides better kill potential. You could also use to stop player momentum, which is vital on falcon and spacies.
I admit that the tranq and nikita support different playstyles. I was once a major nukita user, but I now realize that the tranq is a change for the better. It doesnt help noob or mid lev players, but boosts professional play significantly. Just keep in mind that its something you have to get used to.
Also dont expect pmbr to keep things the same as brawl. The point of pm is to create a new experiwnce: one between brawl and melee. That would be impossible if they dont change things.