There's no such thing as ratings commensurate with hours; one can't equate the two. You're far better off being proficient than having a lot of qualifications, especially if you won't be using them.
If you get your multi rating, that's great, but how often will you rent a multi-engine airplane? If the answer is rarely, then you won't be able to stay proficient, and it's a lot of money spent for something you may not use.
No training is wasted. Getting a new category or class rating will always teach you more, increase your exposure, your background, and broaden your understanding. If it's something you want to do, then do it. If it's something you're doing in the hopes of using, then do it, but be realistic in your approach.
I met a young man a couple of days ago who just finished his multi engine rating. He has about two hundred fifty hours, perhaps a little more, and is a newly minted commercial pilot. He got the multi in the hopes someone will hire him to fly a multi engine airplane. That's not going to happen. He'd have been much better off getting his CFI; that gives him something he can use, and will give him a much better understanding of his craft than a few hours of multi would. For what he spent, he could have done the CFI and CFII.
If you're due for a flight review, go get a new rating, instead. Go do a glider add-on. Learn something new. Get the multi. Do something in a seaplane, or a conventional gear (tailwheel) airplane. Learn to fly a helicopter. Get a rating in a hot air balloon, or fly a gyroplane.
A lot of people make it to their private, fired up with the goal of getting to their private, and then go no further. They stop flying, their enthusiasm dampens, and they find it hard to commit money to to training if they no longer have a goal toward which they're working.
Give yourself a new goal.
Do get your instrument rating. Whether you fly instruments or not really doesn't matter. The training you receive and the application it has to your thought process in your daily flying is worthwhile.
Take time out to enjoy your flying too, without it always having to be training. It's allowed.