Even though my Beastmen are far from done, only having a small unit of Bestigors, 10 Ungor raiders, two Shamans and a Beastlord, Doombull and minotaurs. I have a Ghorgon/Cygor and Centigors coming in. The question ran through my head of a way around Sylvaneth, as later on in time I will be having a game against one. Treelords, Alarielle, I know well that are in the army. Even though I have my Seraphon and Clan Pestilence/Moulder, but that can come later. Being a very pushed-aside army (unless you count Tzaangors but Beastmen provide no support buffs to them), they don't have the variety and power like recent releases. My thoughts are putting down a Cygor, as Cygors are made to fight wizards. Another guess is to try and take everything down as soon as possible, Even then there are two characters (that don't exist anymore both model and possibly the rules in the book) that are good anti-wizards. So it's mostly a discussion of old armies vs newer ones.
The experience I had playing against/for the Beastmen was two books ago I think (prior to the ghorgon/cygors getting introduced for the first time), back when Gors and Ungors were in a single herd together, massive horde-skirmisher style, and could ambush from the table edges. This proved effective surrounding and charging the pesky wood elves, who while they were pretty fast and had loads of weapons (while the beastmen had none), the huge numbers of the beastmen hordes were able to swarm them over. Also it helps that the giants/larger monsters appeared as bigger threats, and wound up soaking up most of the incoming fire, allowing the more numerous units to reach the wood elf lines and attack them at full strength. Fairly effective some of the time, but they also have low leadership, and in the wrong moment it could start a chain reaction causing half your army to scamper off the board. That happened once in a battle too... all started with a unit of hounds fleeing, taking most of the gor herds with them... The addition of some nastier units has given some extra punch to the beastmen, but they still suffer from a lack of shooting options (for the most part, as my lack of an understand of AOS doesn't help you much). My advice would be to try and keep them at arms length, they don't have much of a choice other than to run screaming at you and force you into combat.
I don’t see why you wouldn't mix in some of your skaven. A cygor with the movement of the gors/ungors, plagueclaw catapults and some storm friends would be a fun army that could wreck some stuff.
@Warden Yes, luckily my Ungor Raiders have the extra movement in their rules so hopefully I can pick off a few and possibly distract. I'm thinking of converting the other characters and using them with the old warscrolls if possible. So many of the characters are anti-wizard but now there isn't as many in the updates that doesn't include them. @Bowser Sounds fun Well I do need to make a dream army for Chaos, not just for order. I noticed something too about the Shaman, being capable of summoning a single Chaos Monster on a 9. But I don't see any restrictions on his warscroll about hero chaos monsters, unless it's in the FAQ or in the Generals Handbook. Seems like someone like Skarbrand can be summoned, but not sure on this. https://www.games-workshop.com/resources/PDF/AoS_Warscrolls/aos-warscroll-great-bray-shaman-en.pdf
No restrictions there, as ling as the keywords Chaos and Monster are present you can. Being a chaos wizard he can actually summon most daemons, and can use this spell to summon bloodthirsters for 1 point cheaper.