Throne of Thunder would have started at Duruumu the Forgotten. The Zandallari part and the sewers up to Ji'Kun would have been 5-mans.
Siege would start after Nazgrim, Vale would have been a 5-man as would have the landing.
Both of these would have rewarded gear equal to the last tier or tokens that could be exchanged for the current gear. For example: ICC, End of Time, ToC 5's, Zul'amon and Zul'Gurub remakes - all were the required catch-up mechanic to get folks into the latest tier.
Now imagine if LFR had been around (yes, I realize it was there for dragon soul.)
Suddenly the ICC 5s are now a completely separate raid that goes through each boss and ends with your 10 to 25-man group running away from the Lich King as you try to remove the ice walls and get to the gunships.
The End of Time dungeons become a full raid too. Suddenly Azshara gets a better time to shine, Jaina, Baine and Sylvannas all suddenly have power that makes them a real threat so you know you're fighting former faction leaders. The Nozdrumu fight gets really cool and we get a bigger and better showing from Illidan's betrayal.
LFR allows them to build in a catch-up mechanic that allows for bigger, more immersive and cooler raids. Just thought I'd remind folks.