I actually had a conversation with Higgs (another Night Terrors member) about this recently, so I figure I'll pipe up as well, since the guild I'm in is in a similar situation. Actively looking for the mob, I've found him up once in about a week. By the time guildies who needed the flag were home from work half an hour later, he was dead - with no flags offered in /ooc, so I sure hope they went to another similar guild who actually needed them.
Realistically, I want a challenge. That being, I want to have to overcome the boss in order to progress, rather than having to overcome any of the numerous more-progressed guilds on the server just for a shot at it. What holds a guild back should be whether or not they have the people, the gear, and the ability to counter the mechanics of the fight - these are plenty of limiting factors, and meeting new folks, gearing up, and learning a fight are fun. Waiting around and hoping that you can match everybody's schedules against the limited timeframe that a contested progression spawn is up is not. (I've done it in classic EQ for epics, and vanilla WoW for world bosses, it wasn't fun there, either, and it hasn't improved with time.) And this is only going to become more of an issue as the server becomes more populous. I can understand that the people at the top end of content like contested spawns, though even Sony eventually decided that it wasn't such a good idea in a lot of cases, so here are a few suggestions:
Idea 1: Leave the top tier (or two, or three, as seems appropriate) as uninstanced content. As new tiers are added, instance the lowest of these tiers for guild instanced use. (Say, now that T8 has been added, T7 remains uninstanced, but T6 becomes instanced, for example.)
Idea 2: Move all tiers to the T2 style, wherein there is one uninstanced raid zone, and one instanced raid zone in the same tier. Admittedly, this would require a significant amount of additional dev work, but it would allow people both the enjoyment of the open zones, and a place to go if their raids tend to be at odd times, long after the normal server restart times. The LDoN raids might be a possibility here, if there's worry about expending the available potential raid zones.
Idea 3: As Farine said, with the improvements in available gear, T1 isn't a challenge even to T1 guilds at this point, provided they have enough warm bodies, so an alternate keying method for T2 can be devised. Emp key seems somewhat reasonable, though I wouldn't mind some kind of instanced single boss (maybe even lootless) to use as the barrier for entry.
As to token flagging, from observation it seems that they're rarer in the past couple of weeks. If I'd seen it coming, I would've spent more plat on them and just tokened guildies into T2, but such is life. I won't say that the token rate should be reincreased (I know it's been modified a time or two, and read the threads on it), but I will say that, with Emp usually unavailable (at least, by the time folks get home from their day jobs), tokens are the only way to reasonably expect to get into T2, and thus raid with guildmates, in a reasonable timeframe.
Here's a can of worms: Maybe it could even become the next plat sink. 30k/character for T2 access? (I kid... but it might just work.)