To comment on the MIDI stuff - you really have two options if you want a rig to operate with two separate reverbs or delays:
The complex method: Using a MIDI controller that can send SysEx, you can send messages to the Kemper to set and assign every single parameter. This includes reverb type and delay type. Unfortunately, SysEx is rather complex and you can't (easily) sweep values using an expression pedal, and not everyone has a controller that can send SysEx. I was able to create a setting using my controller for a gig this last weekend where I wanted a tremolo to go from about 60% mix to 25% (where the effect was still on and present but less of a primary feature), and I did so by assigning a button on my controller to send the proper SysEx commands. It took about 30 minutes to figure out the spec for it and to understand the Kemper's guidelines for doing it, but it worked.
The easier, but convoluted, method: This works best in performance mode, though you can do this in browse mode by duplicating rigs. Set up one performance with one reverb/delay/whatever, and then copy it to a new slot (or duplicate the rig after saving). Modify the desired effect to meet the secondary need, and save. You will have two copies of the same rig which you can call up by their slot (or the assigned PC # in browse mode). The problem with this is if you need to make a change to the rig as a whole (less gain, EQ tweak, etc.) - you then need to make that same change twice. Additionally, if you prefer to use the Kemper in a manner where you don't use presets and you flip on stomps like you would if it were a pedalboard, your on/off settings for your stomps will not be retained when switching over.
There's no real great solution, but, as far as I know, Fractal's the only ones that have done this, and done this well, by their usage of multiple signal paths and scenes. Kemper, Eleven, and Line 6 (save for the Helix and X3) operate under a single chain method, and you're pretty much locked in on a preset-by-preset basis.
All that said, back to the original topic, I use a slew of outboard effects with my Kemper. I have a volume pedal at the start of my chain (that also operates as an A/B between my wireless and wired connections), a Morley Bad Horsie wah, and three overdrive pedals (6 Degrees Sally Drive v1, Foxpedals The City, and an Addrock Ol' Yeller). I also have a stereo loop in the X or Mod slot (depending on the performance slot) that runs a Strymon Timeline and a Strymon BigSky. I've found that, for myself personally, the modulation, compressor, and EQ effects on the Kemper are fine for my needs, but the overdrive and time-based effects are lacking. I've been able to get some usable overdrive sounds, but not to the degree that I'd like, so I stick with my own pedals. As far as the delay, the Kemper does a fantastic digital delay and a fantastic shallow reverb. Some of the U2-style delay presets are actually really great, and Meamboboo (sp?) has some really nice reverb patches available. However, a lot of what I play out live requires me to build up a lot of space and ambience, and the Strymon pedals let me do that in a very easy manner, and without having to create several dozen different presets for each delay/reverb combo sound. The Kemper is severely lacking in these respects.
Someone mentioned earlier that the Strymon pedals have their own Sparc chip - this is correct, at least with concern to the BigSky. I don't believe the actual chip used in the Timeline has been published. Either way, they're processing delays and reverbs at a level that I simply don't believe the Strymon's DSP will be able to achieve. Some of the Strymon stuff (Timeline's Ice, BigSky's Shimmer) does harmonies with the sound, meaning, from a programming perspective, that you'd be using a delay or reverb, which it's trails would be fed back into a pitch shifter. This requires a lot of processing power. You can do 30 second decays on the BigSky, and that requires an immense amount of processing power. Something like the Strymon Timeline's dBucket sounds would be relatively easily achievable with the Kemper, though locking it to the next to last slot is incredibly limiting for my needs, and if I can't get a huge 18 second hall sound, I won't be switching over.
So, all in all, I stick with MIDI-controlling my overdrives (via a switcher) and my Strymon pedals from my board apart from the Kemper. I have the best of everything for my needs - a fantastic amp setup with some great compression, EQ, and modulation (when I do need it, which is rare), the beauty of analog overdrives chained together, and the ambience-building abilities of the Strymon pedals. The biggest downside is my pedalboard is pretty massive, and I have to run a snake to the Kemper from my board. But I get the sound I need.