I too have Chessbase and Aquarium. I don't use Aquarium...just not very intuitive and I can get what I want from the other programs. I do have Chess Assistant and it is arguably better than CPT as a pure 'positional database'...but it too is so infuriatingly counter intuitive (for the average guy) that I rarely use it. I know people obsessed with correspondence play (old phrase...more 'cyborg play' now

) gravitate toward those Convekta products but most people have Chessbase/Fritz as it is easier to wrap one's head around it.
TRAINING NEEDS TO BE EASY...IF IT'S COMPLICATED, YOU DREAD DOING IT...so, CPT improvements should not make CPT too complicated. That's my personal opinion. Steffan has been good about NOT making CPT too complicated, so I trust him to continue with that.
I frankly find that for
OTB play where it is just one-on-one and players are left to their own devices, CPT is invaluable in trying to recall 'YOUR' preparation. THAT is its primary purpose. Once I get a good repertoire, I only do my editing within CPT via UCI engines. I really think Steffan could help out there with logical assistance like: the ability to have an engine 'pass' when you are stepping thru your repertoire editing it, to better see what your opponents move might threaten...or what your move might threaten which you might not even be aware of! You can then color code or make a comment as to a trick or potential pitfall to remember. I use this a lot in Chessbase - 'X' (threat) function...unfortunately, once I have imported a PGN file, I lose the ability to do this....and a simple Variation board to follow the analysis out a bit before entering variations.
So, on my wish list:
1.
COLORED SQUARE and
ARROWS -
visual aids are GREAT for training! You might could even use these as 'optional' during recall sessions or even during simple stepping thru the lines which I more often do.
2.
BETER ENGINE CAPABILTIES - 'skip a half move' (X function in Chessbase...essentially a 'THREAT BUTTON')...could help in giving you hints when you can't recall what you should be trying to do or tricks in the position to avoid.
3.
VARIATION BOARD for engine use.
4. Giving you easy options when stepping thru variations to simply
PLAY OUT THE POSITION (or just a few moves to get a better feel for positions you may not have studied in a long time) against an engine.
All good trainers recommend 'playing out' of positionsagainst opponents. Of course you would NOT want to have those moves recorded inside CPT...maybe sent to some temp file you can continuously overwrite.
TRAINING = MEMORIZATION + PLAY...but this needs to be easily done...
not something you have to
close CPT and export the position to an actual chess playing program. Chessbase does have a
'play out against Fritz' feature...exports the position to a weakened online Fritz where you can play the position as long as you like. Something like this... ideally within CPT where you have designated an engine only to look 'x' ply deep (weakening it)would be SO beneficial for actual training
THIS MIGHT BE THE SINGLE BIGGEST TRAINING FUNCTION CPT LACKS!?.
That's basically it...nothing too radical, just ideas to make CHESS POSITION TRAINER better live up to it's name.