My frustration with Mercury is that they typically always just give the lightest weight available for each class or horsepower of outboard. For example, their Mercury Four Stroke series 225 is listed at 478 lbs, though that is also for the 20" shaft version, which I'm assuming the 25" shaft version will probably add another 20 lbs or so? Putting it at right around 500 lbs dry, compared to the Yamaha F200 with a 25" shaft that has a dry weight of 525 lbs, the Yamaha F225/F250 in the 25" shaft being at 562 lbs and finally the heaviest being the Suzuki DF225/250 at 606 lbs dry in a 25" shaft. Comparatively, I'm not sure what year the OP's current model Yamaha F200 is, but I'm assuming it's likely an early to mid 2000's vintage? Which the dry weight for that motor in a 25" shaft version is stated to be 583 lbs. I guess to make a long story short, if the OP's current motor which I'm also confused on because he says it's an F200 but seemed to allude to the fact that it was an F200? Which I don't believe they started making the 4 stroke Yamaha's until 2003?
Anyway, if his current motor "gets along good" as he mentioned in the first post, I'd think that just about any 225-250 hp outboard variant discussed would be as good or better than what he has. Most of the 225's mentioned are all less than the weight of his current outboard, yet with more power, and even the heavier Suzuki motors at 606 lbs are still only about 20 lbs heavier, yet he would have an additional 25-50 hp for output. I think just about any outboard that he picks will do fine, especially if he's "content" with what he has currently. For the sake of argument, let's discuss a hypothetical that his current boat with 200 hp is say 5,000 lbs not including the weight of the trailer. I always like to consider the horsepower to weight ratio, which would put his current setup at .04, whereas the heavier Suzuki 225/250 outboards even if they were say 100 lbs heavier, you'd still have a hp/weight ratio of .044 and .049 respectively.
Long story short, I don't think an extra 20 lbs or so on top of what he currently has is going to be noticeable, especially if he gains an extra 25-50 hp on top of the weight gain. And if he really wanted to, he could always move the batteries around or play around with some weight distribution, though I imagine you also don't want to be too light in the stern and get squirrelly either. Imo, I think it's all going to come down to what's available, the pricing, warranties and so forth. I think just about any of the above mentioned outboards will work just fine and all will have their trade offs. Personally, I'm cheap so I'd go with the "best bang for your buck", which Suzuki is usually always the cheapest and has as good or a better standard warranty compared to the others.