One thing that really struck me as surprising is the overall nerfing of movement speed, in both items and in the Masteries. At times it was pretty terrifying to have a jungler chasing after you with way more movement speed then you have, but you may have gone a little overboard with some of it. I can see why you put 25 of the movement speed from boots in to a champion's base movement to help hinder the effectiveness of rushing boots and giving more variety in your first items, but with the removal of the Force of Nature, a lot of off tanks lose a fair bit of their speed and effectiveness.

I personally love playing as Hecarim, and I would really enjoy building him as an off tank, using his amazing passive along with some movement speed items to really help him perform, but he by far was hit hardest from the overall movement speed nerf, as it being key with his whole play style. It doesn't destroy him by any means, with the addition of offensive movement speed items he could be a decent bruiser, but it really hurts his abilities as an off tank, as he will have to either make do with little movement speed items and prioritize defensive items or lose on a bit of tankiness for some lesser movement items to maintain damage.

My question to the readers is how are some new effective ways to build off tanks to compensate for the loss of movement speed, and also specifically ways to keep off tank Hecarim strong. I also have a question for Riot (if I'm lucky enough to get a reply from them) to ask why did they nerf movement speed from items and masteries, and if they are planning on giving an item that will help tanks and off tanks move faster and give decent defensive stats?

Movement (movespeed) is a fundamentally offensive and defensive stat (simultaneously), just like range. This is because it gives you the ability to "In 'n Out" a slower target, avoiding damage altogether. Movespeed should therefore be balanced such that squishy melee champions tend to get the best of it, squishy champions overall tend to get the next most, and beefy/tanky champions tend not to get more (by much) than squishy champions. There are of course myriad variations on this depending on role, kit, etc., but this is generally a good rubric.

Hecarim in particular makes a good jack-of-all-trades, which is why he is usually built as a bruiser, despite the fact that he can 1-shot most non-tanks if built properly. As far as building for MS generally, check out these items: Zeal (and derivatives), Zephyr, Ghostblade, Twin Shadows, Mercurial Scimitar, and don't forget the boots upgrades; all but Distortion gives some form of direct bonus MS, though Captain boots only affect allies (though if everyone gets them, there are some interesting implications). Of these, I find Zephyr, Ghostblade, and Mercurial Scimitar (Hg) to be the most attractive on Hecarim, though there are other items, such as Hydra, that are also intriguing.

Hecarim's passive doesn't make or break him, he's generally better off ignoring it in builds anyways. As cool as more damage for movement speed is, you're generally better off investing in unique passives on items that boost your overall combat power more.

As for movement speed - it's horrendously annoying stat to offer in huge chunks. You generally create the atmosphere that there is a movement speed arms race, and whoever doesn't take part is going to be left in the dust. As it allows you to chase and escape it has an equal impact on offense and defense, the only other attribute that does this is attack range.

I'm personally a fan of the change, as it was Phantom Dancer was pretty much required for the rather unique mobility it offered. Now that it offers less mobility (and other AS items offer mobility as well) it seems less of a requirement than a necessity. As for tanks with MS, the only time they really need it is to initiate fights - you don't need continuous mobility to stick to targets like melee DPS or enough to kite like ranged DPS. The movement speed alone on Force of Nature made tanky champions unusually slippery for how survivable they are without being able to outrun everyone, especially considering any decent tank has really solid CC - which tends to be the only "mobility" aspect on mages at all.