Quote from GloriousGoose »What's your opinion on Sentinel Tower? It's a different tracker to keep count of but seems like a solid, synergistic win condition. You're running a dense enough core of instants and sorceries to tutor and draw that I think it could be worth running.
I think you're 100% correct when evaluating the [new Lavinia] from a more casual approach. I happily admit that there are many ways to play Commander, and I personally prefer playing more competitively. That being said, here's how I see the new Lavinia:
Lavinia's power is directly proportional to the type of decks your opponents are playing. For me and my playgroup, and the cEDH meta generally, mana rocks are king, especially the ones costing 2 and under. Lavinia causes mana rocks to be non-beneficial sources of mana advantage since she restricts your opponents' casting of spells to their land size. Check out my Memnarch and Teferi Primers. You see the relatively low land counts? More often than not, I only have 2-3 lands in play but a bunch of artifact mana that powers out MORE sources of mana advantage and card advantage. Very few of these effects WHEN I CAST THEM are ever proportional to the number of actual lands I have in play! Lavinia makes this type of mana advantage a liability for these types of decks since they no longer contribute directly to developing your board presence for the important non-creature spells that are played. There are too many playlines and gamestates to describe where the ability of my mana rocks to generate mana that can be used to cast non-creature spells ahead of their casting cost is absolutely crucial.
In my playgroup, it's very frequent that you'll see someone trying to jam a T1 Mana Rock into some sort of T2 non-creature spell (more often than not some sort of Wheel effect). This is almost 100% the consistent playline that I see and Lavinia stops that super effectively. Additionally, cEDH decks run a VERY low land count. This means that the non-creature spells that cost any more than 2+ mana have a real possibility of being unable to be cast with Lavinia in play. Hell, she even stops the earliest, most effective Wrath effect from going off UNTIL T3. If they even get to 3 actual lands in play in order to cast it. This is a very significant tempo loss for your opponents since they now HAVE to depend on land as their primary mana sources in order to unlock their spells.
Lavinia doesn't just shut down "large X spells" or Tooth and Nail type of cards. She causes legitimate tempo loss for optimized decks that run low land counts and the most powerful non-creature spells available. Ad Nauseam decks will NEVER get off the ground as long as Lavinia is in play until AT LEAST T5. Do you see how Lavinia shuts down any type of Dark Ritual effect? What about High Tide? Fast Combo decks that aren't Flash Hulk decks can no longer chain their spells together on time until they have the correct number of lands in play. Assuming they even hit their land drops every turn. Teferi Chain Veil decks now have to up their removal count because there's NO WAY that they can cast a T2 or T3 Teferi with Lavinia in play. Even Food Chain[/CARD} decks will stumble (not as signficantly as Storm or Teferi Chain Veil) because their most common line of play is T1 mana dork or tutor -> T2 double mana dork or tutor -> T3 Food Chain, often seeing rarely seeing their 3rd land since they depend on mana dorks to power out an early Food Chain line. Even Flash Hulk type of decks have to be careful since they can still possibly jam a T2 Flash but now have to be careful about what kind of protection they have for their combo. And her 2nd ability shuts down the new Arcum Dagsson decks that depend on different variants of Ornithopter in order to keep triggering Paradox Engine.
All of this discussion is relevant because Lavinia is a Legendary creature and can therefore be a Commander. That means she can be cast on T2 EVERY game and even on T1 with a MASSIVE degree of consistency. Because her effects are also ASYMMETRICAL, you don't disrupt your own combo lines at all. She's like a one-sided Gaddock Teeg.
So, to conclude my rant/explanation, Lavinia is significant and a very important card for the cEDH scene. For any other type of play, she's just a cool 2/2 Hate-Bear that enforces everyone to play fairly or depend on the inherently slower land-based ramp effects available.