Excellent, we are close to the same page. Like I said previously, new cards that have synergy with mono, duos, and trios. As well as speed and cost or quanta production, both are absolutely essential. Just not too fast.
Every element being meta worries me though, I could only agree if it were to certain extents and kept with the identity of the element. If not, all the elements essentially become gray and lose their theme. Another viable option is to make the elements individual traits boosted yet be mono or duo exclusive. This in theory would make people think twice about using an all around deck VS a mono or duo deck being so great at its own mechanism that it becomes just as attractive, powerful, and fun. Rol/Hope was a fine example of this (minus its easily manipulated weakness.), as well as lavarush.
I agree, mindless additions, overly meta, and stand-alone cards, will be wastes. I would also like to see more variety in pvp matches, more fun that way.