Elixirs are soft sounding strings, to be sure, but I think it's the string material and not so much the coating. I did like them for a fretless bass I used to have (STOLEN!); I had a set on for nearly two years before I noticed a tone change, and I'm picky. If you want any sort of definition in your tone, though, yeah, I'd stay away.
NOW.... to un-hijack the thread...
I prefer the IDEA of tapered strings for the B... but truthfully I don't seem to have much luck. There's a subtle difference between tapered and non-, and I think it's an improvement in clarity when it's tapered, but it's still not great.
Now it's POSSIBLE that it's a bad run of strings I've run into; B strings are notoriously hard to make balanced given the amount of material they have to use and the possibility of One Little Thing Not Being Right on that huge towing cable I put on my bass. I've had lousy luck with B strings ever since I got a 5-string bass (which is why I came to the forum today; look for a new thread soon).
I can tell you I've had good luck with LaBella Super Steps strings. The core is TOTALLY exposed over the saddles, eliminating the issue of trying to bend such a thick string over the top and creating a lot of overtones. I like the sound of them as well - bright and crisp. Now that's taking "taper" to the extreme! It does require an action setup after install, but you may find it's worth the effort.