I currently use the Korg Pa900 the same way you use the T5. I don't use the arranger... Sounds, playback of WAV files (MP3 on the Korg), and the registration memory.
Now, do I sell the Pa900 to get the Pa4x?
OR
Sell the Pa900 to get the highly positive reviewed Yamaha PSR-S970?!?
Hmmm?!?
If you don't use the arranger features at all why not get a good synth or workstation, Kronos, Motif XF,..
I like having an arranger in my arsenal of keyboards. I have the Motif XF6 but getting to audio files is in file mode. Not the best way to do it. I worked at a music store selling keys for 12 years... So I have a collection at home.
I've been gigging since 1991... Korg M1 to Korg O1/Wfd to Korg Triton 61 to Korg Triton Studio 76 to Motif ES7 to Roland BK9 to Korg Pa900
So at this stage of my gigging, my keyboard needs to be light, able to play audio files (my sequences from my other boards.)
I have my backup tracks on my mixer...Sonar VS100 or my new Soundcraft Ui16. But in my duo, it's important to keep my track selection in front of me while engaging our audience.
Workstation stays home... Unless the new Yamaha "Montage" or whatever they will call it is built well with a small footprint and will do what I need for a gig. Here's to wishing!