Seems if weight was an issue for you I would buy the 361 (4.4 bhp, 12.3 lb powerhead). However since you already have a lighter saw that is still running good I personally would go for the more powerful 441 to give you more range in your saws. A bigger saw will cut faster that a smaller one, no replacement for displacement. The 441 (5.5 bhp, 14.6 lb powerhead) is only 2.3lbs heavier than the 361. Now haviing not held each saw at my dealer, which I recommend you do as every saw feels different in the hands, I would actually suggest the 460 (6.0 bph, 14.lbs). The 460 seems to me to be the better buy than the 441, as it is probably about the same price and is the same weight as the 441, yet has another half a horse more.
Now since no one has yet taken a stab at the second part of your question I will give it a go. The advantage to a longer bar and chain are several. First it gives you the ability to cut larger diameter wood if you so needed. Second, the more cutters that are on the chain, the fewer times they will touch the wood, so the chain will cut more wood without going dull than the same chain that is shorter and has fewer links. Third I went to a 24 inch bar on my saw so I did not have to bend over to cut and limb so much. Trust me at the end of the day your back will thank you for the longer bar.
The bottom line is only you know what size, species, ect wood you are cutting. Therefore you are the only one that can answer what saw is best for you, and how you use it. Everyone's situation is different. I went from a 55 cc husky rancher to a 80 cc Dolmar, and I can say I have not even pulled the cord on the 55 in a couple of years. Once you get used to the power of the bigger saws, you can not go back. I would bet you would be the same. Perhaps, as a thought, if you have access to borrowing a 441 or 460, or maybe renting one for a day, I would. That will tell you everything you need to know.