31 lands just doesn't feel like enough with a deck with only 6 pieces of ramp (counting
Smothering Tithe) and an average mana cost of over 4. I get that the entire strategy of the deck is to drop creatures with your commander for free but if someone shuts you out of her by continually killing her, locking her down, or stealing her you likely won't have the mana to cast the other cards.
Maybe you're counting
Land Tax as ramp? If so, it's really not. It doesn't get you ahead on mana. At most it ensures you hit your normal land drop- which is nice- but even that's not guaranteed. It's based on someone having more lands than you which isn't always going to be the case depending on the pod.
Also, you've got to think about how much it costs to cast your commander. She's a 4 drop, but if she's removed once she now costs 6, removed twice and then she's 8, and so on. Kaalia is a commander that a lot of people will kill on sight because of how powerful she can be and how some people build the deck (mass land destruction) so I would expect to cast her at least twice a game, if not more. Your commander is key to your strategy so you're going to need the mana to cast her multiple times.
Going by EDHrec.com, the average Kaalia deck has 34 lands and 10 pieces of ramp (also including
Smothering Tithe). So 3 more lands and 4 more pieces of ramp. That's a big difference.