I heard an idea at one point was adding a new "Banned" list to the formats. But it was called a "Combo Banned" meaning, this combination of cards is banned, you can have one or the the other, but you can't have both. So to use your question specifically, Black Lotus and Black Lotus 2.0 would be "combo banned". Both would be on the restricted list, and both would be banned in conjunction with each other.
An interesting point about your question 2 (What rules do the power break), and basically the main rule is "1 mana per turn" (Whether that is straight up free mana or ridiculously undercosted spells.) Workshop decks have always been the deck design to make all those players play by the same rules (Chalice, spheres, nullrods etc) and slowly over the course of Vintage, even those strategies have been deemed too strong. My point being that they tried "nullifying" the power and that hasn't done really well.
While falling asleep last night, I was attempting to change the P9 so as to have an equally power level (but different). Note, these would all have to fall into a Combo Banned system. Obviously if you have access to both it just exasperates the problem.
Tap, Sacrifice [this]: Choose one
Add three mana of any color to your mana pool
Add <><><> to your mana pool
"Wasted Mox [Color]"
Tap: Add 1 [color] to your mana pool.
Tap: Add <> to your mana pool.
"Recall of the Ancestors"
Draw three cards. <not, NOT Target player draws three cards. 98% the same, but fundamentally different>
Target player takes another turn after this one.
I loved the idea of Tribal Duals...
Tribal Land- Island Swamp Siren
The question that I find interesting is, lets use my examples of the "Tarnished" Jewelry/Lotus. If you had access to both, which one would you use? The new ones are technically more powerful, no opportunity cost to using... but, not our original pretty old school pieces.