Good idea. Sometimes it is as much the challenge as it is the money. Don't get me wrong, I love saving money also.

One reason I enjoy Vintage Machinery, Cutting Edge Engineering, etc YouTube videos is when they fix something. Keith brazes a tooth back on a gear and machines it back. Or Kurtis welding up and then align boring. Will take a look at your suggested fix and report back.
Every time I buy a new battery, I figure that is what is going to happen. That is why I am always looking at 20V adapters.
My 18V system, off the top of my head. Impact Drill, Drill, Impact driver, 1/2" Impact, 4 1/2" grinder, light, circular saw, angle drill, and Sawzall. I bought them used as a kit long ago. I don't think I have ever used the angle drill. The light and grinder eats battery, so I use 110V for those. I do use the Sawzall, and both drills, both impacts drivers a lot. The circular saw ocasanaly.
Another reason I started hanging on to them is waiting for the next voltage jump.

I understand volts x amps, why would they just jump 2V? Could marketing have something to do with it? Maybe some? I keep thinking they will come out with the next new line and the 20V people will feel the 18V people's pain.