Technically as a fighter, low-end to be honest.
Obviously his wrestling is very good.
Business-wise, he is very successful personally and very useful also to the UFC which is why he gets gifted big fights despite being away for years at a time.
This.
He was never great, but was definitely effective in the offensive wrestling facet, and surprised people no matter where the fight took place with how well he used his size, reach, speed, weight, and offensive grappling power/strength.
His striking power was lacking for a man of his build, but he was still able to somewhat surprise and/or temporarily stun some fighters like Heath.
Let's not forget that his hilariously stupid looking ground and pound flurries, while not the strongest single strikes at all, was obviously never something able to be shrugged off unless your chin durability and heart was closer to that of a beast instead of a humans (think Gaethje, Hooker, prime Fedor and prime Hunt) a thousand jabs will TKO more often than one single bomb of an overhand will knock someone out cold.
Other than that, his effectiveness and ability to execute other techniques cleanly was shit. He never was going to win against Overeem and Velasquez or anyone remotely like them, but holy shit did he cower and run and slip and fall in terror like he was helpless prey of an apex predator going into overkill mode.
We all know what we think of Alistair as a fighter, and horsemeat or not, he runs through Lesnar every day of the week, no matter the year or rules. This is not a knock on Alistair or Lesnar or anyone else, it's just the truth.
Mir vs Lesnar might be 5 wins out of 5 losses for both, if they fight each other 10 times.
Let's just say idk if he can keep Derrick Lewis on the ground long enough to finish him or even come close unless Derrick decides to give up an RNC instead of muscle out or stall out, because while Lesnar is surprisingly good at offensive wrestling, he isn't DC good to say the very least.