Hello Michael
Yes, you could do that, and connect the access point with a trunk link to the specific VLANs that you have configured. Such a network looks like this:
This means that you would have to make sure that all VLANs that are used for all SSIDs are made available to the appropriate ports on the switches that serve the APs. When the network gets large, this can be an administrative nightmare.
Imagine having 50 access points, with 12 different SSIDs, on a network with 12 switches, and you want to be able to provide various SSIDs to different APs. The whole VLANs configuration will be very complicated, and will also put a lot of overhead on protocols such as STP. And then imagine you want to add 3 more SSIDs to five specific APs. You must go into each switch and add the appropriate VLANs to the appropriate trunks and so on… You could just allow all VLANs on all trunks, and use VTP for VLAN pruning, but that’s not necessarily good network design (remember broadcast domains?). Now imagine all of that on a network with 500 APs and 100 switches. 
As the network gets bigger, the complexity increases.
The purpose of CAPWAP is to simplify this. With CAPWAP you can configure a single VLAN for all of your APs, and have the intelligence of the AP and WLC automatically create the CAPWAP tunnels as needed on each AP.
I hope this has been helpful!
Laz