You may be fine with the UR22 Paul, if it’s just yourself recording at home and you don’t see yourself ever recording more than 2 tracks at a time, whether those be one Stereo pair or 2 separate Mono tracks, such as guitar & vocal.
But having a quick look at the C12+ & the UR22, it might not be worth switching from one to the other. It seems that they’re very similar.
The UR44 looks like it has some extra ins & outs and the extra headphone port, but if you’re getting on with the C12+, you may not even need that either, especially if you might still use your MidiSport 2x2 as well.
You can definitely use your MidiSport 2 x 2 instead, although consider using them both if you do get a UR 22 or 44.
I use the MIDI In & Out ports on my TC SK48 main interface for my V-Drums, but I also have a Roland UM-550 MIDI only interface [no audio], offering 5 MIDI Ins & Outs, as the name implies for my 88 key Midi piano, sequencer and sound modules all to hook up to.
Like most DAWs, Cubase will recognize more than one MIDI device, if added/setup in the Devices>Setup section .
So the upgrade to the UR line [22/44] may not make all that much sense when looking at the over-all setup of Ins/Outs & MIDI ports of all 3 devices.
You may be just duplicating what you have already if you get a UR22 & still plan on using your MidiSport 2x2. Unless there’s a major difference in sound, you might stick with what you’ve got [at least for now] and save some cash for other things - like some really neat VSTs 
.