I once did a dissertation on teapots, and looked into this very subject. I've looked at Le Creuzet teapots, and you've confirmed what I thought would happen. For a teapot not to drip, the edge of the lip on the spout should be fairly sharp.This allows the tea to divide cleanly. If the lip is at all rounded, the last bit of poured tea follows the curve and either drips off, or runs down the outside of the spout.
The best non-drip spouts are found among Georgian style silver teapots, where the metal was thin, and the lip was sharp.
If you remember the similarly shaped aluminium teapots that Woolworths used to sell, with the cast aluminium spout, they are certainly among the best pourers.
They might not look so good on the table, but they do the job. An alternative to these can be the thin enamelled steel teapots.