I ran into this too. I'm primarily interested in PvE, so not very concerned with not having FTL. I ran for a while using "assist Pantero" (my main tank) in all my attack macros and that has worked well up through 50.
However, I messed about with things a bit last night to make things more flexible:
I left bar #1 the same, but set up an alternate bar #2.
I copied over my DPS macros into new ones with a "cast @focustarget <spell>" format, then
set up a seperate follow macro on my toons that has "tar @focus" then "follow" on the next line
At that point, all I have to do is broadcast "/focus Pantero" and broadcast Shift-2 to get everyone on the correct bar.

Still pretty low tech, but allows me to set a different leader simply by focussing someone new.

It took me a little while to figure out the "tar @focus" thing, and there may be better solutions out there, but it works well for now. If anyone has other ideas, let me know.