See, I see the two cards as being different. Different enough to know which one I would like to see in the game.
Treldon's card being a spell card means you need to consider carefully when and how you play it. I also like that the mechanics sit nicely with the theme of the card and with Life as an element. To me it's a card that makes sense.
I looked at the link Zawadx posted for a similarly named card. After reading the associated replies to Xenocidius' card (including the original idea linked within post, that was involving mutations) I would have to agree with the other posters who point out that mutations and generating copies become more of an
or
related thing.
I like Treldon's card and can see myself using it. Whilst Xeno's I can't. I guess I like the fact that you know straight away what the effect is for Treldon's card, you can predict it and be strategic with it. Xeno's needs some thinking about and you could end up with a collection of somewhat useless creatures, especially if you've been loading them up with adrenaline, or if they are poisoned anyhow. I don't exactly know what it is, but I just can't quite wrap my head around Xenocidius' card and its effects.