The reason you're not enjoying yourself as you rush through the level 50 MSQ is because...you're rushing through it. Take your time. Enjoy the content you're playing.

Don't just rush to the endgame. This game isn't designed for that.

The need to complete the story up to patch 2.55 before accessing Ishgard is not a design flaw, but intention. I hate to say it, but if you're one of those people that live only for endgame content and tend to just rush leveling content, then this game will be endlessly frustrating to you.