Given the extremely low risk of certain types of hacking, hackers ought to be hacking all the time slowing the game down to a really boring crawl for everyone else. We have the same issue stoping mages from going overboard on astral scouting and ritual magic. Similarly groups get tired of a face smoozing every single NPC we don't gun down.

This got me thinking about running a game with only one archetype? Could you do hackers in bunker game? Could you do a ritual magic hit squad game? What about a bunch of PC fixers?

The benefits I'm see are that you could really dig into an aspect of the game the game. In an all hacker game you could paint an incredibly vibrant matrix because you can totally abstract the a facilities floor plan. More over if the PCs are doing over-watch for NPCs fighting NPCs physical combat can be run a strictly GM fiat. You could have an NPC entry team pinned down by drone fire with an about to get flanked. The PCs then have x number of rounds to do something to change the situation -Spoof the drones, hack open the blasts doors behind the entry team, screw with the flanking team etc.
Another benefit I see the radical change to the feeling of stock shadow run tasks. A team of bunker hackers having to go and get new hardware is kinda scary. Likewise for mages a meet becomes a little dicier without muscle.

I ran an all Decker (SR3!) campaign once. It was fun.

One of the problems that springs immediately to mind is having the entire group create characters who are very good at what they do (which is largely the same thing for everyone) without feeling too similar to the point of redundancy.
You'd need to make sure that each character had their own specialty; if they all end up looking 95% the same then it'll get boring. I think. Maybe.

I've run an all-Awakened game before, in SR3. All full magicians, in fact. That was pretty easy, though, since magic is a very flexible field to play in. With everyone belonging to a different tradition, no two characters came off the same.