There are alot of big changes coming so lets get down to brass tacks.
Edit: How did I miss this one?
Resilience: No longer reduces the amount of damage done by damage over time spells, but instead reduces the amount of all damage done by players by the same proportion. The other effects of resilience (reducing critical chance, critical damage and mana drain effects) have not changed.
Wow. Just. Wow. This makes resilience HUGE. This also makes long term classes like Melee/Warlocks much stronger if matches can be drawn out long enough through defensive play. Inccoming Season 3 all over again? Hrm. Time for everyone to reroll Druid imo.
3.2 Arena Changes
-The newest season of Arena gear can only be purchased if you meet the requirements with your 3 or 5 player team rating. Rating requirements form 2 player teams can still be used to purchase previous season of gear.
This is probably the biggest change as the 2v2 Arena bracket has been the go to bracket that most of the Arena population plays due to the ease in which people can come together to get games in. Naturally, 2v2 is inherently imbalanced as many comps live and die by the comps of their opponents. A renewed emphasis on 3v3 and 5v5 will likely encourage players to compete in a seemingly less Rock/Paper/Scissors type of environment. However, this is only conjecture as it seems to be harder for casual PvPers to coordinate some of the larger team sizes as evidenced by the complete dearth of teams in 5v5. In addition, casual players may continue to flock to 2's as they may see the Season 6 (Furious) gear as 'good enough' and as such, keep the 3v3 and 5v5 ladders relatively bare.
Remember, the strength of a bracket is completely dependent on the number of active teams. Only time will tell to see if the casual crowd embraces these other brackets and if Blizzard lowers the rating requirement of the next tier of gear to tempt causals. My best guess is that Blizzard would create 2 tiers of Season 7 gear, one that the casuals can easily obtain and one that the pros will want, much like the tier 8 and 8.5 gear from the raids. Let's see if I'm right.
--The Entire Arena has increased in size by 25%
Good. This should give people more room to work with both on top of the platform and while running around the edges.
--Mounts can now be used in this Arena
Great. Not being able to charge into combat sucks. Not being able to catch up with a travel form Druid pillaring you with the entire map sucks.
--The position and collision of the crates on the central platform has been modified
Awesome. There have been times where, due to the geometry of the crates, I've had failboat fears or had others LOS my cyclones while still blatantly in LOS. This should help eliminate those issues and make it less random or prone to the effects of latency.
-Ruins of Lordaeron
--Alcoves have been removed from the starting chambers
This is an interesting change as it prevents players from kiting between the two starting chambers, LOS'ing and drinking. Naturally, this will make RoL a faster map and reward teams that seize control of the central tombstone.
--Two line-of-sight tombstones have been added to the slime pool on the southern side of the map
I'm not sure how large these tombstones will be, but it seems they will be a good place to run towards if the other team dominates the tomb with AOE snares.
--The collision around the central tomb has been smoothed out to prevent players from becoming stuck on the terrain as often.
I have mixed feelings about this change as the current tomb showcases experienced players from complete nublets from the way they move across the tomb. This change will likely allow melee to stick to their targets easier, speeding up the match even further. I think in the end, this will be a positive change as people will likely complain less with regards to the map geometry.
Note: WHERE ARE THE CHANGES TO RING OF VALOR (A.K.A. RING OF BUGS?)