Hi! I've also used MT Power drum kit pretty extensively, and it has a lot of great functionalities (building preset grooves, etc.). Another great drum set that you can use with the free Kontakt player is Drum Mic'a (https://de-de.sennheiser.com/drummica) which I think has a more natural sound but it takes a lot more work to get working properly. I would also look into Spitfire Labs (https://www.spitfireaudio.com/labs/) which has a whole bunch of great sounding free vsts! (esp. keyboards, strings, synths)
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Yeah, I with you on the soft piano being too muted. I haven't found one of equal quality, but I've used the keyzone classic (http://www.vst4free.com/free_vst.php?id=2848) a few times and it sounds ok if you set it back in the mix a bit. But, eh, I wouldn't call it quality, really. Sorry that I couldn't be of more help.