I don't think Kazuha is better than Sucrose and Venti when applying crowd control to enemies. Venti can summon a massive vortex that can suck in lightweight and heavy enemies when they freeze. Kazuha's crowd control is relatively small in his elemental skill; however, his elemental burst can still cover many areas. Also, Sucrose's elemental skill and elemental burst can pull in enemies and group them at a single point to deal damage to them. So, on the sole basis of crowd control, Venti and Sucrose are better than Kazuha because of their massive area-wide application.