How does monitoring via the direct output have anything to do with being able to PLAY an instrument?
You think it is funny?
Actually morerecords has been teased by all the crowd here but he is actually right.
He doesn't have to explain why he wants to monitor DIRECT because that's the right choice for any musicians and producers whom care to have a faithful representation of the performance they are recording, and usually people who work with music know this very well... otherwise the albums we listen to would be very crappy
So it has to do with playing ability because having a delayed, jittered, instrument is the worst thing that can happen in keeping the feel with the instrument you are playing, so it is necessary to get the proper inspiration/involvement with the instrument, so yes it can really affect your playing and if you haven't ever noticed this thing, probably, you have to learn to play better your instrument and specially you have to play something like a real piano, which has no sort of jittering, to understand what's a "direct contact" between your hands and the instrument
Read this if you want to go deeper
Especially since morerecords was talking about more than one external keyboard being monitored while looping midi, I'm considering this an on topic troll at this point.
That's the reason why I hate forums... people like you who feel so superior... who have no worries in insulting people calling them trolls... and you don't even consider the eventuality you are wrong, or you've missed something, or you don't have his needs because you work in a different way or you don't have the knowledge and that's why you work in a different way.........
Lot's of assumption, BTW, direct monitoring is crucial and unfortunately there isn't a solution to what the OP is asking... (if there it is let me know!)
To get good timing, jitter free response, you have to turn off the PDC, not use induced latency plug ins and use analog synths or very low jittering digital synths
Plus a thing like sync gen for your timing and a thing like expert sleeper for triggering your external synth... and maybe an hardware sequencer to record all your midi sequences. Unfortunately for now, that's it.
Also, if you think about it a bit, if you want a plug in that does a complex processing which requires added latency to perform the calculations, that latency will be unavoidable... you just hope it is latency and not jittering also
So, the workaround is to plan your workflow very well and do everything that's playing, composition, sequencing, before... than commit to audio and work with processing and any induced latency plug ins you want