On my extremely durable Cleric, I'm very satisfied with the difficulty of solo content. I don't die that often, but I do end up pushed to the limits of what I have at my disposal to stay up. The only downside is that a lot of the difficulty comes from mobs respawning on top of you while you're clearing an area out, which really hurts my squishier alts.
(The mage in particular feels like a bad deal - you lose a lot of versatility and a lot of durability in exchange for a bunch of different ways to do ranged DPS, but it doesn't feel like the sheer levels of damage are that much greater.)
Also, the exp curve has been pretty much perfect for my playstyle - I dinged 30 on the very last quest in Scarlet Gorge, and I was always within a level or so of the quests I was working on. (I could see this being more of a problem if you were also doing PVP and dungeons for loot.)
The Dynamic Game
Like most non-instanced content I've seen in other games, Rifts and zone invasions are a lot of fun when precisely the right numbers of players show up. Soloing a minor rift is fun, and beating a major rift with 3 people is a lot of fun when all the pieces fall into place. Less fun is having 6-8 DPS show up, wiping, and having the public group scatter rather than stick around to see if anyone can switch into a tanking and/or healing role that could win the fight with the players at hand. Finally, as I discussed yesterday, scaling for really large groups sometimes seems to result in an extremely lengthy but non-threatening fight.
In general, I stop to fight any rift or invasion that I run into, and I generally try to join each zone-wide invasion event at least once to see the sights. If I do get a repeat, though (I think the Werebeast in Gloamwood spawned five times while I was working on the zone), my willingness to drop everything and ride all the way across the zone for a few dozen planarite drops rapidly. Likewise, it gets a bit old when you have to fight off an invasion to respawn your quest hub, you go off to complete the next few quests, and return to find the place destroyed and camped by mobs yet again.
Crafting
I posted about crafting last week, and I've made modest progress since then. One thing that's striking about the system is that you really don't need a lot of raw materials to get crafting skill points - you can make an item for a guaranteed skill point and then salvage it, getting a third to half of the materials back. My level 30 character has been able to harvest enough stuff to feed two separate crafting alts, both of whom are now crafting level 30-ish gear.
The catch is that obtaining recipes can be more challenging. Either you need reputation with local adventuring factions - obviously, my alts don't have this at low levels - or you need to do daily quests for tokens. Worse, the daily quests offered are based on your crafting skill, meaning that you can lose access to them if you gain too many points. If you're near a cut-off between tiers, you're better off NOT gaining that next point until you have enough materials to gain 10-20 points, so you can open up a new work order to replace the one you're losing access to.
Outlook
The next few levels should be interesting, as I unlock 32-point root abilities and then have a bit more flexibility to pick up mid-range stuff in a secondary soul. I also haven't tried any PVP or dungeons yet, so that's another area that I can hack away at going forward. Finally, there is another faction to try, and apparently two leveling paths from 36-50. There's definitely a lot of stuff left to do in the game.
That said, the rift content is the thing that this game has and the others I could be playing right now do not. So far, it's been hit or miss, and the real hits have come at times when there are fewer people around in my level bracket (e.g. because I stopped to level a pair of crafting alts while everyone else leveled past my main). Right now, I expect that I will pay some additional money for some additional time in Telara, but I'm not running out to buy the six-month plan.