While I agree that a gifting system would be nice, I have to disagree with you on trading creatures purchased with real money/jewels for those that we get free each month.
For myself, I only just started back in March, and there are many creatures from previous years that I'd like to get my hands on. Unless it's through one of the events, and I get very, very lucky, that's not going to happen except through trades. I recently traded a cash shop pet for eight pets from 2011-2012 - I consider that a good deal, since most cash shop pets only cost around 16 jewels, and you get several hundred for a $10 donation. Unless it's one of the cash shop auctions, and you really get into it, there's not a creature in the cash shop that would cost you the entire $5 purchase of jewels - not even in your wildest dreams.
Just a bit of 'for your information' there, so you have an idea how the cash shop works. The creatures there are very cheap - heck, I bought all but one of the ones in my 'cash shop creatures' clan, and still spent several hundred jewels on the 8 jewel random crates - which netted me quite a few older creatures, too!
It's a good deal all the way around, in my opinion