In thread "Developer Q&A - The Answers!", developers want cards to be “conditionally powerful”, not "all-powerful". But i think tribe synergy element is 1 important aspect within “conditionally powerful” as well.
Like podfather and torchwood are "synergy giver" of pea tribe, whereas pea pod is "synergy taker". Pea pod is only “conditionally powerful”, provided 1 primary condition: if it can survive long enough to grow strong. Without podfather and pea tribe, pea pod is not "super strong", but still "acceptably strong". In this case, the benefit of podfather and pea tribe are just secondary condition that could be forgone, a deck with or without pea tribe, pea pod is still “conditionally powerful”.
I give a green shadow example deck: pea pod, sweet potato, black-eyed pea, doubled mint, lily of the valley, muscle sprout, grow-shroom, mayflower, bananasaurus rex, plant food, plucky clover, espresso fiesta.
In this example, I got 2 pea, but they can stand alone and still strong, so I don't need "synergy giver" like podfather. Those 2 cards are just “conditionally powerful”, they are not "all-powerful", but there is no tribe element !
A few months in future, more and more new event cards being introduced, we will have many more cards that are strong enough to stand alone without their "synergy giver", just like pea pod.
Let's say when there are 7 types of cards (4 each, total 28 cards) could stand alone, with 12 tricks makes a 40 cards deck. We may decide "Ok, my deck don't need "synergy giver" anymore, those cards are strong enough to stand alone". The consequence? Tribe synergy aspect is no longer a special element in this game.
If only 1--3 heroes can be strong without tribe element, we may say "they are special". If many heroes can have such deck, the importance of tribe element will be very small. So, if tribe element is ignorable, what element makes PVZ better than other card games? I collect those“conditionally powerful” cards, especially event cards, ignore their tribe. At the end, everyone will have very similar deck. It will be simply P2W.
