Barbra was already a top recording star when Funny Girl opened in the spring of '64, and just because you "long for" a stage production, doesn't make Funny Girl's book any good. The script was tailored to Streisand's talents.
I'm for a revival, but it won't be easy and who knows how much they can actually change/fix with copyright and royalties.
Back in the dark ages (mid-1970s) I worked on a summer tour of FUNNY GIRL starring Carol Lawrence, then a reasonably big name (we sold out) not only from WEST SIDE STORY but from her many TV appearances.
She sang the ballads rather well, but was much too stiff to ever do the comedy justice. The end result was just "Why did they bother?" Even the rest of the cast seemed to feel it.
I may be proven wrong, but I can imagine a Lea Michelle FUNNY GIRL being much the same.
That's fascinating! I would love to hear more about the rehearsal process.
I saw a regional production of Funny Girl (no one famous, the girl was good and giving it her all) a couple of years ago, and when leaving the theatre I overheard a woman say to her husband "I bet Streisand was amazing," that sort of summed up my feelings as well.