Titanforging originated as Thunderforging from MoP which later became warforging After Throne of Thunder. The biggest problem with TF over WF was while WF could add a few ilevels to gear TF could add dozens and completely invalidate raid drops if you happened to get a stupid enough RNG chain from a world quest.

On top of that due to how itemisation worked for various classes and specs you could sometimes get drops which were a higher ilevel than what you had equipped but if the secondary stats weren't useful the higher ilvl meant nothing. This coupled with the devs removing Master Looter meant players couldn't even pass the useless drop to someone else because you were only allowed to trade ilvl downgrades which didn't even bother to consider how secondary stats could be significantly more important at times.

As for the problem with Legendary drops, initially you only got two per character. That was it. If they weren't your BiS you were fucked and raiders literally rerolled toons when this happened.

Regarding the interrupt Legendary you had that was the ring wasn't it? It was deservedly criticised because it was not only poorly designed originally but also it wasn't class specific so everyone ran the risk of getting it at first and compared to other options it wasn't any good. It wasn't until the devs removed the drop cap as well as letting players work towards a Legendary that the system became player friendly but Blizzard in their eternal greed implemented artificial timegates to keep players active but the other limits in place could outright kill the performance of some characters if they got shit Legendaries due to how game changing some of them were regarding both class mechanics and sheer dps output for some.