picked up Diablo 3: Reaper of souls because I've heard good things about it "fixing" things with diablo 3, such as the real money and gold auction house.
While I'm upset that a "trading space" is gone, the "loot 2.0" system is amazing.
I suspect that gear upgrades are dependant on your level and what you're currently wearing for rares and legendaries. I often find gear that is exactly what I'm building into. Gear is relevant agian and plentiful. At one point during my gameplay starting a new character I went back to town because my gear was full, and as I was evaluating upgrades and scrapping/selling the rest, my party was progressing and they were hitting bosses so fast that I kept getting pulled into the fight from town, got new gear that was upgrades, and went to scrap the old and got pulled yet into another boss fight about 3 times before I was ready to start grinding agian.
The new crusader is a re-imagining of the paladin class, and I have to say, it's by far my new favorite class. If you were a diablo 2 fan and remember the "hammerdin" build then you know how powerful it was, you can make a spiritual successor to that build that is much more powerful. I don't want to give any spoilers, but "blessed hammer w/ limitless rune = pure insanity win"
The guild system is limited in the amount of players and there's not a whole lot to do with your guild such as large scale raids as you're still limited to 4 players within the game, and there doesn't appear to be any sign that's going to change. With enhanced difficulty scaling the game being "too simple" shouldn't be a problem.
Adventure mode is great for gear runs, and the unlimited paragon levels bring in uniqueness into play. New tiered out difficulty levels are great too.
I have to say I'm quite impressed, and I was severely disappointed in diablo 3 in terms of replayability. Reaper of souls makes diablo 3 quite fun and if you kinda enjoyed diablo 3 but didn't love it, then you will love it with the expansion, I know I've fallen in love with it agian.
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Some things I hope to see in the next inevitable expansion, of which I guess there will be 3 more 70-80, 80-90. 90-100
-necromancer like class, witch doctor doesn't quite satisfy my need for a massive undead army, it feels more like a druid replacement.
-Custom games for more than 4 players, PVP and PVE seem to lack in the scale compared to the days of old. Matchmaking 4 player seems decent for just campaigning through the game, just not flash gear/grinding runs.
-If auction house is removed, something needs to take it's place to form a market within the game, trading forums outside of the game is too troublesome to take part of and coordinate the trade. "black market" trading was a good model to that of the "ebay" setup. There is enough 1 slot rare mats in the game to take the place of gold as a currency for trading, hopefully the community settles on one and finds an effective way of continuing commerce. What is lacking is a good area to do it.
-runes/runewords were so awesome and sadly still missing. The ability to give one class a useable skill from another class for extremely unique builds is also still missing. I can't tell you how much I miss the ability to give a necromancer or paladin a spamable teleport, or staking skill levels to that of double what the game was designed around.