1) Not nearly all of the penalty cards are woth -7.
1B) Those brackets are actually unnecessary.
2) Just because you encounter them doesn't mean you deserve the extra 7 points.
2B) Sounds more like you want a lottery for BP.
According to your idea, players who don't encounter penalty cards are at a disadvantage. Many players don't mind playing against Taljion, Raeth, Elvis, Oxen etc. These cards aren't even Elo banned.
The big problem though is the DJ Korr, Tanaereva, Ambre and Morphun cards which do pose a nuisance. It could be better if players using these particular penalty cards could be matched up with only other players using the same penalty cards.
Though you can almost completely avoid such decks by using a low deck.
The only problem I see in DT for now is sometimes a 25* deck gets matched up with a +30* deck.