Heroic Saurfang is again the same as normal saurfang in most of the ways that matter. In heroic mode, he gets more blood points from all the sources of damage he does. Oh and everything hits harder, but that goes without saying, right? One extra added BOOYA of hitting harder is that now, damage is proportional to BPs. The more BPs he has, the more damage everything he casts/hits with does to your toons. And yeah, once a new mark goes out, he goes back to hitting like a pussy for a short amount of time until his BPs rapidly increase again.
This makes it significantly harder to heal as marks go out faster.
One thing that makes this really heroic is the adds. A commenter noted that I missed out an ability cast upon the adds, being Scent of Blood. The 80% aoe slow makes kiting near impossible. If they touch you, you are pretty much dead. CCing them and killing them cleanly before they get to their allocated DPS is vital to beating this boss. Allocate your DPS to them carefully and ensure that those adds go down fast and without touching anyone. Slows, knock-backs, stuns are vital to making sure the DPS have enough time to kill those adds before they attack anyone.
Aim to hold off the first mark until AFTER the first set of adds go out. If you are getting the first mark before the adds go down, you need to have a look at what is causing the blood points to go up so quickly. Are the adds hitting someone? are people standing too close together for blood nova?
Healers need to look at their healing much more closely now. 6-7 healers is recommended, probably 7. If you can, get 2 holy paladins as they can heal the first 4 marks leaving 5 healers free to keep everyone else alive. Keep the paladins on the ranged, and let the other better aoe healers heal marks on melee.
This brings me to an extra point for healing - marks transfer melee damage done by saurfang as well as some extra just for fun, that's how it works in normal mode, too. BUT! In heroic, the difference in Saurfang's melee hits from 0 BP to 99 BP is really crazy, mark healers will really notice the difference, and they will also notice the difference in healing a clothie with the mark and a plate wearer with the mark. Try to keep your pallies healing the clothies if at all possible (your clothies should be at range anyway, so this should happen naturally).
If in the first 4 marks a melee is chosen, the paladin should heal it, but communicate that they are going to swap to the first ranged marked after the first 4 go out. 2 paladins makes healing much easier, but of course, this isn't necessary, the theory extends to any class. Make sure that marks are allocated out to healers, (ranged marks to specific healers, melee marks to specific healers). Keep as much mana for the 35% mark, as things will start going batshit insane for healers at that point. Save all your tricks for this point, and conserve your mana as much as possible up until this point.
This is a hard fight, there is little to no wiggle room. Stuff up an add, and healers will be unable to heal toward the end of the fight as marks start cascading out. Stuff up a mark, and Saurfang heals, extending the fight. Good luck!