Do Not Go Down An AWA Road. There have been several posts suggesting AWA's are good in a shortage market. Wrong, while some people may reap a short term benefit there is a flexibility there that will allow that to become easily erroded.
AWA's can be changed and if one or two of your workforce accepts the new amendment then the rest of you will be painted as troublemakers. The signees will be working different conditions while you are not. Not a good thing for harmony.
When it comes time for you to re negotiate the 50% numbers will see some people targeted to sign the new one. They may get more, leaving the other 50% less. Oh you can stay on the old one, again with different T&C's. You may also see the targetees losing or having their benefits erroded. You should always remember you will have to give something up that may not be evident at the beginning, but might make your life less fun.
If there are several versions all new hires will be given the worst AWA and told to sign. There will be no indication of another, again having people on different T&C's.
AWA's are very useful in seperating workforces and identifying "troublemakers" as well as constantly tweaking conditions in an employers favour. On an industry level they again fracture and divide, making animosity and losing the cohesion that works for everyone.
Collective bargaining has it's own problems but at least everyone is on the same page. Employers are in a good position now but maybe the pendulum has swung a bit too far and we should remember the further it swings one way the further it has to swing back. That won't help anyone.