I have an old style Wave, and The Swiss Tool Spirit and the Swiss Tool-X, and others, but these 3 are the better suited of the multi tools I own to your questions, so I will confine my reply to these.
Out of these three I like the Wave scissors the best, followed by the Swiss Tool-X then the Spirit. The Spirit seems to be left handed scissors which I find a little off putting.
Both of the Swiss Tools have the same can opener, and it is far better than the Wave's which you already like.
The Wave's knife is easier to use one handed, but it doesnt stay as sharp as the Swiss Tools blades, and the Spirit has a funny blade which you may not like. I suggest you try handling a Spirit before you buy one to see if you like it. The Swiss Tool-X seems to have the better blade of the 3.
Both the Swiss Tools have an Awl as well, which the Wave does not.
The Spirit is around the same size as the Wave, but the Swiss Tool-X is slightly bigger.
From what you describe, I think either the Spirit or the Swiss Tool-X would suit you well, but I would try the Spirit first if I was you just to see if you like it. The Swiss Tool-X might be getting a little too big for your liking, but I think it is slightly better out of the two. The Swiss Tools are built better than my Wave, and with better steel.
I dont like the new Wave very much and I still havent made my mind up weather I will try a Leatherman Charge yet.
If you have any other questions other questions about these, fire away and I'll try to answer them the best I can.