diy controllers

hey guys so I've been on here multiple times asking the dj tech tools team about different diy controller ideas. I started with gamepad ideas but bleh mapping isn't my cup of tea. then I thought about making a mixer out of my noavrion remote though it broke in a separate incident. I moved on to buy a korg padkontrol which is awesome and a uc 33 e evolution made by novation or some other good company I believe. my questions* were " can stacking devices eventually be too much?" for example can looping to many midi devices get out of hand through midi? will it affect my laptops usage? I know there's also the route of stacking there USB ports on to a USB hub. would a powered hub be better? would it allow the laptop to work better with my devices or would it be usage draining as well on a older Microsoft based laptop ( HP g62 478ca model number) as well as an ( HP elitebook.). I plan two combine these to devices Ina mixer style midi device for scratching as well as sample pulling and effect use. which brings me to my next question, for scratching if I replace one of the sliders on the uc 33 e with a better crossfader should I expect a difference? when it comes down to scratching can a midi crossfader compare to a external mixer?