Benefits of Upgrade?

[Indytraveler83]

Ok guys so here's the story:

I have a 54 gal corner reef tank, and a 55 gal freshwater mbuna tank. The 55 is getting up there in age and on a pressed wood stand. I'd like to upgrade it to something like a 90 gallon sometime this year. (cannot be more than a 4ft tank)

It would be easy (and cheap) to just give the mbuna a bigger tank, but I don't see myself gaining alot by doing so. (All I get is more of the same fish) Alternatively, I could switch the mbuna into my 54 that's currently a reef and set the 90 up as a reef tank.

The question:

What could I do/keep in a 90 gallon reef that I cannot keep in my 54? I keep a mixed reef (but lps heavy) setup with lots of smaller fish and 2 flasher wrasse as my prized possessions.

 

[Wolf89]

Small tangs. Tomini, convict, whitetail, kole, blue eye, squaretail. Foxface is one of my favorites

 

[Gareth elliott]

Some fairy wrasses come to mind.

 

[Indytraveler83]

Good suggestions, any other fish or types of fish/inverts, or anything else I can do with the tank that I can't with my current one?

Just trying to weigh if it's worth the money/time of rebuilding my current reef, or if I'm better leaving it alone.