Combining heroic and normal lockouts for ToC to make people “not feel obligated to raid as much” is silly because there’s zero commitment required to complete it. It’s six bosses with (nominally) zero trash and it’s a complete joke on normal mode; even the most braindead pugs from over a decade ago would clear it in an hour or less. Removing normal mode from the itinerary won’t make people raid heroic mode for an hour a week and then call it good, it will just make people feel obligated to head back to Ulduar for chase items instead.
This is fine, I really enjoy Ulduar and don’t mind having the opportunity to spend more time there, but the fact of the matter is that the only people actually affected by this (people who are doing ToC hardmodes) will actually have longer, harder time of things, and let’s not pretend otherwise. People progressing hardmodes will have reduced access to loot to help get through them (for example, if you’re working on Anub hardmode, that’s 5 bosses a week worth of ilvl 245 gear you’re not getting), and people farming hardmodes will be going back to farm Ulduar after ToC.