Stock location isnt whats horrible, its the aiming.
Tweeters are best off-axis. meaning you dont want them pointing at you. Which is what our cars do.
I redid mine so the tweeters are pointing at each other and slightly down. With a good set of comps (Rainbow profi's) and good power (Eclipse) off an uber grade Head Unit (McIntosh) it sounded phenomenal.
Back to the OP.
That location isnt good its just to busy. The sail panels the best place in our cars, just need to hack them up and turn them into masterpieces. Otherwise the next best place is on the A pillars, about 4" from the bottom aiming at each other.
Thats it before I did the bondo and repainted them. Now I currently have the stock tweeters there again (sold out my equipment) and it sounds pretty good actually. Its all about location!