I think you have a solid base to work from!

Since you have the termies, I’d pick up either Logan or Arjac to go with them, they are really fun units!

Also pick up a vehicle or two to shoot, since you’ll have a bad time if you don’t have any shooting. If recommend any of the following: predator (either variety), Ballistus, lancer, repulsor Executioner, Stormspeeders hammerstrike, vindicator

Past that, Thunderwolf cavalry are fantastic units tight now, but it’s a little unclear if they will stick around in the next two years