Just finished watching tape on Siyar/Millender.
Siyar has definitely slowed down since the Thatch fighter, he is essentially a fighter that will stand in front of you and brawl with you. He trusts his chin and his technique isn't good but he has natural power. His striking is sloppy. He is essentially banking on landing his wild hooks to win in a standup fight.
Millender is a very skilled rhythm fighter that knows how to use his length, range and distance and has an arsenal of weapons to use. Millender has a 76' inch reach but his long arms makes his length seem even longer. Thiago Alves is a very skilled standup fighter but he couldn't get inside the reach of Millender because of how well he controls range. Max Griffin is very quick and has a great stick and move game which initially gave Millender trouble but if you plan to fight at range with Millender you are going to have a lot of problems which I think Siyar will if he can't knock Millender out and Siyar is very stationary at this point.
Standing up, here are the two key points to the fight. This is where I think most of the fight plays out.
1. (Counter striking) Millender with throw one strike, whether it's a jab, straight cross or hook and draw out a punch from you and he is really skilled at countering that punch by slipping and countering with a straight right or head kick. Watch how low Siyar's hand's are after he throws something and resets, they drop close to his waist. Millender is going to have a field day countering Siyar and will land something really flush.
2. (Clinch work) If Siyar's gets tied up in the clinch, he will be in trouble with Millender who is really tall and long and will have leverage to pull Siyar's head down for a big knee. Siyar tries and punches his way out of it which won't work (improper technique, i.e Rich Franklin against Anderson Silva) against a very skilled striker in the clinch who will have length and leverage.