Klipsch love them or hate them.

Taters....I agree with you.Back in the day when there was less competition they could hold their own.Certainly not the case today,but I will buy their components at swap meets and such because there are still followers and it's an easy sell

From my own experience what the Klipschorn Loudspeaker needs is a bigger mid range cone and larger flare say a 3" cone?. That would alleviate the mid range shrill/harshness (for want of better words) and allow the mid octaves to sound unstrained and uncongested on certain types of music. The tweeter could be Improved upon also.  On the plus side they a very a revealing Loudspeaker and can sound delightful on certain recordings. Massed choral works are a let down to my ears. The pluses outweigh the minuses for me in stock form. As I own two horn speakers that sound better than the stock Klipschorn,  do I spend money and modify/Improve them or just leave them for what they are and enjoy them for what they do well? 

I owned and modded a pair of Heresy's. It took a lot of doing to get them close to right. But played late at night, through tubes, at low volume and the sound was really engaging. And, although folks often discuss how loud they go with a few watts, I found them unbearable past 80 to 85 dbs. 

From my own experience what the Klipschorn Loudspeaker needs is a bigger mid range cone and larger flare say a 3" cone?. That would alleviate the mid range shrill/harshness (for want of better words) and allow the mid octaves to sound unstrained and uncongested on certain types of music. The tweeter could be Improved upon also.

I’d say the midrange horn of the stock Klipschhorn is the bigger problem than the driver itself, but nevertheless I find your proposal makes sense. My own speakers are build or "modeled" around the Belle Klipsch by one Simon Mears in Brighton, UK; meaning the bass horn is largely similar although the mids and tweeter horn + drivers and crossovers are completely different. Moreover the build and parts quality is substantially better. The 2" exit B&C DCM50 midrange compression driver used here sports a 5" (presumably paper-based) composite diaphragm with a 2" voice coil, which in regards to midrange compression drivers is almost unheard of (actually this driver is more or less a modern, permanent magnet clone of the old late 20’s RCA MI-1428B field coil midrange compression driver); usually the largest diameter diaphragms used in mids comp. drivers today is 4." The tractrix midrange horn of the "Belle a la Mears" is build from CNC-machined stacked plywood, and together with the B&C midrange driver delivers a full-yet-precise, utterly unrestrained and uncongested sound with no harshness of any kind. Indeed I find it to be some of the absolute best midrange I’ve ever heard. Which brings me to:

... do I spend money and modify/Improve them or just leave them for what they are and enjoy them for what they do well?

My recommendation would be to try and have your cake and eat it too, and have the Klipschhorn midrange and tweeter units + horns and crossovers completetely modified from ALK Engineering or Volti Audio. It won’t be cheap, but you would attain a one-package solution with 105dB sensitivity, almost full-range, and stellar overall presentation (relatively affordable still) - quite rare these days.