It was already on the eShop once before and I don't see why they haven't put it back on I could care less if its 3D or not I just want to play it on my 3DS like I do with the other zelda titles from the eShop.
^ Link to the Past hasn't been on the eShop (if it had, I'd have gotten it). Four Sword was, and I've got that. LttP has only hit Wii's VC so far, and if it hasn't already, will probably be amended to work on the WiiU as well.
If LttP does hit the 3DS's eShop, I don't think it'd be as a VC game (SNES's resolution is higher than the 3DS, which matches the NES's specifications). It'd be interesting to see what they'd go with though.
I wouldn't mind seeing LttP on the eShop as a 3D classic. Nothing really has to be changed about it, but having a top down perspective with a bit of 3D effect would be perfect for the game and wouldn't just make it a complete port.