To be fair, it's only around 20 days longer than what we normally wait between Coil patches (official Heavensward release is 238 days after 2.4, early access is 234 days after. Time between 2.0 and 2.2 was 212 days. The time between 2.2 and 2.4 was 215 days). It feels longer this time because patch 2.5 was released 3-4 weeks earlier than expected. At least we've been given 2.51 and soon 2.55, so there's a bit more to chew on than normal. If they hadn't delayed the expansion by a month then it would have been pretty much on the normal schedule, but I'm happy that they are taking their time to get it right.
Yoshi-P said that patch 2.5 Part 2 will have a significant amount of content, but I think it'll likely only be the 3 hours of main story quests and maybe some sort of open world event. He also said that there will be minor patches between March 31st and June 19th but that they will only bring QoL changes and not actual content.