AAS Player is a straight rompler, no tweaking required indeed.
Except the possibility to alter the volume setting there is really no way to personalize the presets, there is no options for layering, neither are simple effects like reverb, chorus or filter cutoff present.
The presets are pretty good, showcased by the free Swatches collection, they consist of "bread and butter" sounds suitable for most styles of music.
But as there is no way of shaping the presets in any way they can easily be recognized in the mix, and thus be in danger of becoming dated pretty quickly.
So like a linear video game, once you have played through it there is really not much to come back to here, unless you invest in further expansion packs at $39 a pop.
It's simply provided freely in addition to any AAS bank.
So you can buy any AAS bank you want without having the synth it is made for. You install any AAS bank on your computer, it installs (or updates) the player in addition, do you have the synth or not... it doesn't matter. Therefore you'll be able to use all the AAS banks simply with the player without having the synth (of course without the ability to tune at your ease the patches included with these banks, but it allows you to use them "raw" in your compositions).
And the same copy of the player is compatible to any of these banks. No need to install several copies of the player.
All the AAS banks are so beautiful that even raw in the player they can have a great interest.
Conclusion: buy any bank from AAS... you get the player with it.