BEEN THERE, DONE THAT! I feel your pain, being 5' tall...gorilla arms (sleeves) have always plagued me!
I would NOT mess with the armhole shaping AT ALL. You need the armhole (cap) to be an exact match to the armhole shaping of the body.
I would bite the bullet and rip out the sleeve caps, and 2" down past the armhole bindoffs (thereby removing the 2" before the armhole shaping begins).
I knit a sweater this past winter...and I had to knit 5 sleeves to get two good ones. The E-N-T-I-R-E sleeves.
Frogging (especially for proper fit) is a part of the knitting process.
:grphug: BEEN THERE, DONE THAT! :grphug: Group Hug!