When I started, I didn't know what to expect for my experience in-game. I left the starter guild on one character thinking that maybe I'd find a new guild quickly, but didn't. On another character I was sent a tell to help someone start a new guild, for 10 gold! which was a great deal for me, as I was a level 6 paladin wearing tattered leather armor. But after helping his form the guild, he booted everyone out, so I was left guildless. A week later or so, on yet another alt (I know, I'm like that) I was again asked by someone to help start a guild, for 50 gold! I eagerly quit the starter guild to help, and the people who helped him all got paid and were roughly the same level, so we all ventured out into Mithra and had a blast - my first real group on Uthgard. But now it's been 3 weeks and only one other person in that guild has logged on, and even then only for a moment.

So my thought is, it would be pretty handy if there was an NPC one could talk to that could reinvite a character back to their starting guild.

As I have today made a new character yet again, I realize how helpful the /AS channel is and I see a lot of grouping opportunities I did not see before and do not have out of the starter guild.

Any thoughts on this idea?

Maybe a slash command can do it too, if its easier than making a new NPC

Good idea, many new players made (and still make...) the error to quit the starting guild to help create a new guild for so hard to get golds at the beginning with no possibility to return in this starting guild.

As senior programmer, i dont see any difficulty to add a npc (something as: Hail <name>, welcome back to GuildA or GuildB or.. , make your choice my friend !)or a slash command (as /returnguild <starting guild name>) to do that.
The only thing necessary to do that is the need to do something for the QoL of players.
But for now... its only a dream.

starting guild depends on race and base class, no need to tell to the NPC/Slash command