The way they drew tits in the 90s was better. Reasonably sized, worked well within the limits of the typical budget. Today it seems like they prefer floppy monstrosities or washboard chests for some reason. Sure Ryoko looks like she's been wonderbra'd even while naked, but it turns out that's fine on what is ultimately a cartoon character.
Also typical of 90s anime, they had a horrible allergy to plot. It started off pretty interesting, seems like they're set up to go somewhere, and then they move heaven and earth to make sure nowhere is gone. In the end they kind of go off on a few tangents, skip major plot points, character, and relationship development in favour of spending screen time waffling around, and finally flub the ending.
Ayeka is fine when Ryoko isn't around. She seems much worse than she is because the writers find it more interesting to have Ryoko around at all times.
Ryokofags kindly remember that literally the first thing Ryoko tries to do is murder Tenchi, and she's incredibly selfish. If she wanted to spend time in the nude with me I'm not going to object - but Tenchi does, so at some point maybe consider what he wants? I think it's supposed to be understandable that Tenchi keeps his distance from both of them, and I for one can see his point.
For me the major attraction of Ayeka over Ryoko is the fact she does need to be chased. Something achieved without effort seems worth the effort put into it. There's also the 3D consideration that if a woman seems too easy it's probably a trick of some kind. Or she's a massive slut who will bounce off you as quickly as latch on. Tenchi doesn't know he's in an anime.
Tenchi is spineless, but relatively justified in that spinelessness. 'Muyo' literally indicates 'useless' so they advertise it going in. Anime likes to pretend that monogamous virgin marriage is still a strict cultural norm, and Tenchi Muyo is one of those shows. We the viewer want the harem ending, but Tenchi, avatar of righteousness, disagrees. The previous is a problem because none of the girls particularly deserve to be rejected, so picking only one is also unrighteous. Finally, at first he wants all these irritating bitches to fuck off back to space, thanks; and even when he later warms up to them, he has no reason to believe they want to - or even can - stay on earth. Materials external to the show indicate he likes them more than he lets on but knows if he advances in reciprocation it's likely to sever his relationship with one or more of them, which he's very much against. They too hold strong monogamous virgin marriage norms, even when they say they don't.
While this is quite a few reasons, they aren't necessarily strong, nor hold up to close scrutiny. It's merely better than having no reasons at all.
Seems to me like Tenchi has become the base of many very useless harem protagonists, most of which don't have even the shallow thought put into them that Tenchi got.
Although they skip a lot of plot, it also seems like they often get away with it. Modern anime could learn this trick so they could perhaps finish things in 12 episodes once in a while. Not everything needs to be painstaking depicted. E.g. the plot of Charlotte could fit into 12 relatively evenly paced episodes, but wasn't planned well. The last two go by really fast, but even still there's far fewer "Huh, why did that happen?" moments than Tenchi has. E.g. why doesn't Ryoko want to kill Tenchi anymore? Imagine all 12 episodes were that fast, and that's roughly your maximum plot for one season to contain.
This series includes Ryo-Ohki, Ryu-Oh, Ryoko. I assume these names were chosen by someone who was new to the whole idea of language and/or self-awareness.