I'm not so sure I agree with the premise that overshoes don't keep your feet dry.
Having recent 'upgraded' my winter gear today's bad weather gave me an opportunity to try it all out. se5 to Croyden Ikea
Altura Nevis jacket, Altura tech over trousers and Gore MTBII overshoes. 8 mile cycle to Ikea to buy a mouse mat (well I needed an excuse) I couldn't work out whether I was damp from sweat or the rain, and did it rain, but on arrival I was quite damp under all the ear. The same on the return journey, so 16 miles in all.
The only part of me completly dry was my feet. overtousers covered the top of the overshoes, so no running down the leg problems.
Thumbs up for the Gore overshoes.