I have a 2016 500HO and ever since day 1 when I give it gas/throttle it takes a great amount in order to get any speed out of it. 
I'm wondering:
1.  If the transmission is working correctly and actually shifting to the next gear...
2.  The brakes are somehow catching as I do hear a constant brake sound for the rear brakes...
3.  Somehow even though its not indicated on dash the 4WD is stuck to on...

I've ridden quads since 1985, and never have I driven a "utility" one where where it requires nearly full throttle to reach 30mph.  I did not buy it for speed, but still its ridiculous.

Anyone else have this issue?  Also the cooling fan no longer functions so I think there is a blown fuse.

[2015 Z Force 800 53/Trail EPS]

Clearly there is something very wrong. The 500HOs run pretty good. Does it roll easy in neutral? Air filter and prefilter clean? Any flashing lights on? How about the valves-when was the last time they were checked?

Air filters are clean, and no flashing lights on dash.  I don't think valves have ever been checked.  The total miles on it atm is near 200 so it is still quite "new." 

I will check to see if it rolls easily in Neutral next week when I will be at that location.

This is definitely not normal for a 500HO.  Mine will run at 30mph all day at about half throttle. I would guess you have a stuck rear brake.

how do you know the 4x4 is stuck on?   That will also zap power. 

You would smell a stuck brake after a fairly short run.

i would recomend a valve adjustment because in the breake in hours the valves may get a bit off and need a adjustment. But i din't think thats your only problem. Check the brakes on the rear omethimes they get stuck and apply some brake force all the time.  if you have warranty you can ask a dealer to take a look if it's something wrong with the fuel injektion

Mine was delivered with the handbrake adjusted too tight and I didn't notice just around the back yard, but soon found out when I went for a run on the road. Much smoke and burning smell.

I tried moving it when in Neutral and it seemed easy to push forward/backward.  I was looking at the tach and on flat terrain I'm about 4700rpm to maintain about 20 mph. 

I'd take a close look at your belt and CVT.  Possible it's slipping.  Sounds like you ruled out the brakes though.  And although I agree that the valves should be checked and adjusted, It sounds to me like a drive line issue or possibly you are in low gear and need to adjust you shift linkages.

[2015 Z Force 800 53/Trail EPS]

Yeah sounding more and more like something with the belt or clutches to me with those RPMs. Wonder what it tops-out at?