Challenge for you, annoyance for me. I hate those missions in Factions and Nightfall. At least in Prophecies they can be skipped. You'd have to redo them due to stupid NPC's, bugs in the map, or simply a tiny mistake which caused a whipe. At least in EotN they added to shrines and non-required NPC's so you didn't have to restart all over again if something went wrong.Another thing is the lack of polish and details in some of those quests. For example GW1 Thunderhead Keep. It took many failures for many of us to finally get the quest and complete it. There are actually some thinking and planning involved, like keeping the king alive while holding the gates. Another example was Elona Reach. I lost count how many times I failed that quest during my noob days. But that was part of the challenge.
As for map travelling, I had been saying it should be free since forever. After that I suggested a cheap flat rate based on level, instead of base on location. My necro runs around with swiftness on all the time, so I just run her from place to place to save money. But honestly 4 silver coins to travel from one place to another is very expensive.
So, naturally, a lot of people from GW1, including whole communities moved to GW2. Only to find a game that didn't support their communities. You can't have alliances, you can't play with everybody.
Now, alliances may be the wrong word here, but just see them as an extended guild structure. Actually, what GW2 has is almost complete. The solution is (functionally, not talking about technically) simple: add the ability to make a chat for each of the guilds you're member of. I am member of GWO. But I'm also a member of GWOA. This guild is a guild which consists of all members from the GWOnline Alliance. Had we had the option to create a chat channel for that guild (/g goes to your "home" guild, /g1 goes to the first guild, etc), we'd have the most important part of what made alliances fun to use in GW1. The ability to communicate and facilitate playing together.
Which comes to the second part ANet really screwed up: lack of ability to play together. I cannot meet up with random guildies. I cannot meet up with my friends. Why not? Because I'm on Aurora Glade and they're on different servers. That and nothing else. At least GW1 has had an international district where people from all over could meet, even before the opening up of the districts. Ok, you couldn't do FoW or UW together, but you could do every single thing else. In GW2, I cannot even do dungeons with my friends because they happen to live across that big pond.
Those are the things I miss and those are the things that will really make the world look alive.