It's actually really nostalgic when you leave your town for ages, and you come back to it, it brings back memories, and that just increases your interest in the game because it feels like it's been around for ages, hence the weeds etc.
Another reason i like it is because, if your town is a mess, it gives you something to do, mixes up routine because you get a chance to beautify your town again, and then you can breath in the fresh AC air once you've done with a sense of accomplishment, getting your town back on track is a nice task.
i never had the older games, but i agree with this sentiment. once, i had to stop playing for three weeks, and i came back to a mess. it was nice to spend hours fixing everything, but once you have the beautiful town ordinance you won't have as big of a mess to clean up. and if the rafflesia bother you, you should change to the beautiful town ordinance to avoid them. i think it's worth it if you're not going to play for a long time.