The little one π's and two π's are entry-level products, and should be judged for comparison as such. However, as I said, I think the KSN 1038 tweeter is a good sounding device, particularly for their cost. It has flat response and low distortion, whereas the annoying KSN 1005 peaks in the vocal overtone region very badly, giving it a "spitty" sound which I suspect is the single biggest thing that people don't like.

I would not pair a high-efficiency 8" or 10" midwoofer with a 1" compression horn because this is to essentially have two midrange devices. If building a four-way, then a transition from 8" or 10" midrange to 1" compression horn is perfect. But if building a two-way system, I'd rather have a tweeter that is tuned a bit higher because that allows the system to deliver greater bandwidth. After all, a 1" compression horn shares over three octaves of operating range with high-efficiency 8" or 10" speaker, so pairing them together wastes a lot of bandwidth.

One of my favorite little bookshelf speakers of all time used a JBL Profesional Series 2115 - which is an 8" full range midwoofer - paired with a KSN 1038 tweeter. The only parts used were a 0.5mH coil in series with the (8 ohm) woofer and a 0.33uF capacitor in series with the tweeter. The coil tamed some rising response in the 8" driver and the capacitor attenuated the tweeter to match. Functionally, the speaker was crossoverless, like current models. This was a "Professional Series one π" speaker, and it combined a $200.00 JBL driver with a $10.00 piezoelectric tweeter, and it was probably my most popular model in the 80's. Sounded fantastic, and there are still many, many units out there, with happy, long-term owners.