Before, there was little room for unupgraded decks in PvP, because playing PvP with an unupgraded deck was economically not worth it. Even if you could win some electrum from other newbies, grinding AI3 would always be faster.
Now people can start PvP right away and get some decent electrum, or so I guess, so it is a change for better in their case.
With a partially upgraded deck you have a choice - either play unupgraded and use your experience rather than upgraded cards to win, or play upped PvP and I can guarantee you you will meet people with partially upgraded decks there too.
The problem is that PvP needs a way to match people of roughly equal strengths, or otherwise newbies would have to avoid PvP which is not good. On the other hand it's impossible to find you opponents with equal score because you would have to wait too long until someone with equal score presses the PvP button... so a compromise is needed (unless you can suggest something better, if you do, I'm eager to hear your suggestion).