Actually, the ARR era dungeons can be run solo... buuuuuuut, there is a catch. You can set dungeons and trials as 'undermanned and unsynced' by clicking on the small button in the top left corner of the Duty Finder that looks like a cog wheel). This then removes party requirements for every duty (dungeon and trial and even certain raids) in the Duty Finder allowing you to enter them completely solo. However, going into, say, Stone Vigil solo as level 40 is tantamount to suicide. In these situations it's better to get a high level friend to duo with you and run you through them, but that does kind of defeat the 'solo' aspect (you could also hold off and keep levelling to a higher level and enter them then as you'd have a much higher chance of survival).
SE did eventually learn from their mistakes though and main scenario dungeons and trials in Shadowbringers allow you to take a party of story npcs called 'Trusts' in with you instead of having to form a party with other players, but alas that's just for SHB content and not earlier content.
GLA/PLD did have an AoE hate generating ability called Flash that was gained at level 6, but it was removed at Shadowbringer's launch recently after constant player demands to add an AoE damage attack at that level instead, so now we have the weaponskill Total Eclipse at that level instead, which basically does the same thing but does AoE damage as well. I still miss Flash's simple utility however.
Well, a lot of that is SE looked at their earlier FF MMO FFXI which had a fully customizable Job system (where you could add a secondary Job to the first one and at higher levels unlock customizable abilities), and saw that players were still just finding the most optimal path and sticking with that. And hence FFXIV has continuosly stripped down ability freedom in preference of a default ability path based on your class/Job's role. I do miss certain abilities that were formerly available (such as being able to set low level healing spells to GLA/PLD such as Raise and Protect), but new abilities do compensate for that mostly.
Really, all SE have done is taken the player's blinders off - no matter how liberal or varied the ability system may be in how you can set abilities, players will always inevitably find the 'meta' setup that gives the best return for the least effort, and will insist on only using that (and attacking/shunning other players who dared think outside the box - FFXI suffered from that terribly as I mentioned). Of course the trade off is everyone more or less looks and plays the same, but it's a small price to pay.
Either way, welcome to Eorzea!![]()