Just finished a TAS using the old SNES route
http://tasvideos.org/2119S.html for beating the game, most copied from the latest published GBA TAS. 13791 frames in total. Can most likely be optimised further, such as using the JP version, but I don't care.
The run saves a lot of time, compared to SNES, thanks to the faster text, especially in the Triforce Shrine, as well as faster screen transition. But because of the long intro at the start, that you can't skip, it ends up being 312 frames slower.
The same route as the current SNES TAS can't be done on GBA. As the Superjump made up to the Hyrule Castle wall does not work. The second part of the glitch, with the doorway to reach Ganon, works differently in GBA as well, which seems impossible to do.
And you can't use the Fake Flippers glitch, JP 1.0 only in SNES, for an alternative route which real time runners use to beat the game (See here for the record
http://www.twitch.tv/andy/c/4909901).
In conclusion: Doing this on GBA will just be the same as an old SNES route but slower due to GBA changes. I can't see any reason why it's worth to be published.