Re: Dead end?
Ultimately, if it bothers you that much, you should leave. The question is whether you'll find any other dojo more congenial: whether the things that bother you are particular to this dojo, or whether they are more generally characteristic of aikido (or even martial arts training).
Some people seem to get techniques immediately, and some seem to struggle more. In the cases that I've experienced, the people in the first category are more likely to quit after a fairly short period of time. Early success is often illusory (what looks good to an inexperienced eye may look a lot worse as you develop more expertise; that's what's behind the "I'm getting worse!" feeling that so many of us experience), and when those who have had an easy time of it early on run into something they can't just breeze through -- or when their sensei or sempai become less forgiving of newbie mistakes -- they become discouraged. They're not used to struggling. Meanwhile, for the people who have struggled since day one, it's just how training is, and they keep on putting one foot in front of the other and making progress. No matter how quickly you may seem to pick things up, I expect that you'll be told over and over again to work on the details and the fundamentals, no matter where you train.
As for "big flying ukemi", is this a thing that's emphasized at your dojo? Some dojos really go for this style, others are more restrained. I don't have any axe to grind about which is better, but "big flying" would certainly seem to be riskier. Your sensei is the one who will have to answer for it if someone gets hurt in training; it's his call whether you can/should do that kind of ukemi at this point. If it's what your dojo does, don't worry -- you'll get your chance.
Re: weapons and suburu: different dojos put a different emphasis on weapons. No aikido dojo that I've ever heard of will allow an "actual fight" similar to kendo sparring, though. If what you're after is partner practice or kata, this may just not be an emphasis at your dojo. I'm a huge fan of weapons kata, but I have to tell you, it's just about as austere as suburi. Weapons training, in general, is a lot less exciting than it looks in the movies. Or, perhaps it's more accurate to say that for a certain nerdy mindset, it IS exciting, but in an unconventional way. And, you only get there after a lot of repetition and a lot of detail (the d-word again!).
Finally, your fifth kyu test will be set by your sensei, so why do you think that your training is not going to prepare you for it?