It's all a matter of personal taste and music style how many effects are needed adding to the core dry sound. No matter what gear I use I always prefer a small amount of short room reverb (especially with headphones) since that's what my ears hear from a cab speaker when I play. Some styles demand a lot of effects, some don't. Most guitars on albums goes through a DAW where effects are added afterwards in mixing.
The most important part is that the real dry amp sound must be there to begin with and this is where I think the kemper really shines compared to other digital units I use. In other units I must use much more effects to cover up the bad dry sound.
I think the effects in the kemper are very high quality and cover most needs, but it's good to know they will release more effects for those who want them. None of the available digital units can do it all for me though and it's impossible for one unit to ever cover and copy all great harware effects.
The amp and cab sound is what's most important to me by far. The effects are secundary and are always available in different ways.