Thank you Jalex !
1) bpm : I have not make big change on this, enter the menu BPM then X+UP increase by one, X+DOWN decrease by one.
then press TRIANGLE ( it's an alias for START on ps vita ), you can change the SWING and the DIV ( which is the step length).
just double check when you are enter in bpm menu that you are able to change swing and bpm. Should work. Or I may have post the wrong VPK file... It's possible i had made a mistake on this...
It's working on my ps vita, so I'm a bit worried with the file I have put on the internet....
There seem to be a regression on this release on the PBSynth synth engine which does not work on track 0, I will need to double check. Yesterday night I had an issue with it... Today not, so there is a thing to double check. which is weird...
2) now if you are outside of a menu you can change the submenu with X+Left or X+Right
UPDATE
1) For the X key to delete note will see if it is better, I will tell you. But seem to be better yes.
2) For the parameter lock, it could be great to do it like you describe and will change the color of the LOCKED parameter. There is some addon to bring in the file format to be able to lock them, so there will be some wait before it is available. This feature need to be done rightly. expect some time before it is available.
For the "sequencer in the sequencer", I will add what we call here "table". It is a matrix which will allow to change lot's of different parameter in a step.
google "lsdj table" and you will understand what it is.
Look at 'lgpt' or 'lsdj' and you will understand what it is.
It will allow arpegiato, change osc really fast for the same trig.
This is planned, but this one is a big change, will have to wait before it is 'released'.
It will need another file to store this table. But will be really usefull 
Believe me it will bring really more !
Have you try polyrithmic ?
Go to PSH and don't enter the menu.
Press O+LEFT it will remove one step each time.
Have fun 