Originally Posted by Krynul
While I agree that FoN wasn't the ONLY option available, it was the strongest on the largest number of champions. Other items were situationally better, but you could always count on FoN.
Don't fool yourself. Warmog's + Spirit Visage =/= Warmog's + Force of Nature. The former is strong, but the old combo was about 50% stronger by my estimation. It just doesn't compare.
It's not supposed to be equal to. However, whenever you bought FoN, it was either for the MR or for the health regen passive, with the other stat being just a nice little bonus. The health regen passive in particular was not that useful unless you were also building Warmog's. Now, you can get that lovely health regen passive along with a massive amount of HP without having to pay extra/fill up two inventory slots, and you can do so even if you're against an essentially all-physical team.
-Most- players in season 2 were buying Abyssal on tanks that had any AP scaling instead of FoN because Abyssal is quite a bit cheaper and increases their damage output through both +AP and the mr shred aura (which also helps increase the damage of your APCs, many of which are too long range to really benefit from having their own Abyssal), and tanks often need that extra damage to help make themselves something that can't simply be ignored, especially tanks like Cho'gath who also have pretty decent AP scaling, and most of the true tanks do magic damage for what damage they actually deal (such as Leona, and Abyssal would help her passive do even more damage due to the aura).
Honestly, I loved FoN also, but I got to where I was pretty much never buying it except on Mundo because it was just too expensive, and Mundo was the only champ it truly synergized well with, where you were always wanting all the stats on it and making good use of all of them.
On most any other tank, you were wasting a lot of the item's stats. More often than not, you'd just buy the Negatron cloak and wait forever before upgrading it, which means you only really needed a Neg Cloak's worth of MR, making pretty much anything else that builds out of Neg Cloak and is significantly cheaper than FoN a better option.