If you read the dev diary the other warps aren't going away, they're just changing and not even in a bad way. I've seen two people say they purchased Stellaris because of the fact it had 3 types of FTL instead of one, or that they want a refund because of these changes and plenty others saying how disappointing or saddened they are..
A bit dramatic, a bit idiotic to say the least. These changes do not harm roleplay, if anything it adds more. Being able to find random wormholes that could take you across the galaxy?! Hell YES. If that doesn't enhance the roleplay I don't know what will, not only does that present roleplay opportunities but it also adds a strategic opportunity. The idea of sending a fleet through a wormhole, entering some distant unexplored system full of squishy aliens while having aggressive first contact policies just makes me moist. On top of that, we are essentially getting the ability to create our own Mass relays/star gates.. Who can honestly tell me that isn't cool as heck.
Stepping back from the roleplay thing, war is an integral part of the game. The unfortunate thing is that as it stands war is boring, tedious and .. did I mention boring? Bigger number always wins in the meta right now, and the current 'one fight to end all fights' way the game plays right now is super unsatisfying, wars don't feel rewarding they just feel like mindless clicking with the most interesting part being when the enemy fleets runs away and you briefly have to pay attention to where its going so you can send your ships there. With this change at least we have the opportunity to bait an enemy into a system where their shields are useless, while your ships are decked to the breasts with armour and your enemy is defenseless in that fight? Come on - that sounds awesome on it's own. Imagine fighting the Unbidden, or Fallen empires? Now there is something ELSE you can do besides spamming ships. There are advantages you could set yourself up for.
Having terrain advantages is amazing, on top of that we can expect planetary invasion changes and the current war goal system is going bye bye. Basically everything we related to wars that we have wanted changed since launch is being changed and people are complaining because to do it they had to change FTL. Note- the key word is CHANGE, not remove. It's still there, just different.
It is all so good, I am hyped. I can't wait to see the planet invasion changes and what they do to fix or change doomstacks.