they seemed to be the same as LFR except there was a kickback for standing in AoE on the towers (this was wing 2).
And there you have it. Generally, LFR mechanics are dumbed down like that. The principle is there, but the consequences aren't (or are much lowered). That AOE will bump you from the tower in normal too. Flex is pretty much "normal mode lite" and not "LFR harder"
I've done very little LFR in SoO so can't really comment there, but some examples from previous raids -
Lei Shen - if you don't soak the blue swirly Bouncing Bolts, you get one add to deal with in LFR. In normal, it will spawn the add, and bounce again (making another blue swirly that needs to be soaked or it will spawn an add and bounce again), potentially infinitely. His Fusion Slash doesn't bump the tank back (and potentially off the platform) in LFR like it does in normal
Primordius - if, as a healer, you dispel someone in normal, you remove both the beneficial and bad buffs from someone, so you don't want to dispel unless someone has multiple bad buffs. Each add killed only has one charge of buff-giving. In LFR, best as I could tell, dispelling only got rid of the bad buffs, and left the good ones, and there's 3 charges to each add's red puddle.
Ji'rokh - if you get focussed by a lightening ball in lfr, and don't leave the pool, you probably won't wipe the raid. You will in normal. Early on, before everyone was out gearing it, you also pretty much had to stand in the pool, as quickly as possible, if you wanted enough DPS to take the boss down.
Garalon - if you don't pass the pheromones around in LFR, there's a limit as to how high the debuff stacks. Not so in normal. Also in LFR, if someone goes under him, there's a limit as to how often he will Crush - again, no limit in normal.
Sometimes, though, mechanics are totally different - Durumu normal's color add phase wants you to find 3 red adds and kill them, never ever reveal the blue, and the yellow isn't there in normal. The cone-shaped AOE that he casts occasionally will bump you back and kill you (a pure and simple one-shot mechanic) in normal, while it doesn't do much in lfr. The maze is the same though.
As for heroic, I haven't done a ton, but in general, they add stuff - sometimes fairly straightforward (at least in theory) and sometimes pretty complicated. Many of the ones I've seen are some kind of mechanic where if you do it right, you get the extra DPS necessary to take the boss down. Some of these exist in lfr or normal but have complications in heroic (ji kun has a buff you can grab while under effect of the feathers, but you have limited times you can fly in normal, and more limited in heroic, plus there's nest adds that Must be tanked in HC, this requires two nest teams with tanks involved in HC), and some mechanics are totally new to HC (Stone Dogs in MSV, for example, has things that need to be activated and have certain people move in certain ways to buff the raid). There are also often other things you have to deal with at the same time (more / different adds on Horridon, stuff that has to be dodged during jinrokh's storm phase making it impossible to stack up for healing). And the bosses and adds have more health and will kill you harder.