Klipsch love them or hate them.

Horns provide a very forward, immediate sound, with lots of presence. Too much presence, having a severe "cupped-hands around a mouth"/"pinched nose" coloration that quickly becomes irksome. The worst speakers, by far, I've ever heard for vocals. The ones I've heard, anyway. But very dynamic, if that's your priority and you can live with the extreme level of coloration they possess. They do mimic the sound of the PA systems at rock concerts, which may be why rockers don't mind them. When I lived in my Band's house at the age of 21, our PA (Altec Voice Of The Theatre A-7's) did double duty as our stereo speakers.

Horn speakers (or horn hybrids, as they mostly are) span many varieties, and I don't find above descriptions to be a common denominator on their better implementations. With my own horn speakers (based on the Belle Klipsch) as a point of reference: rather than sounding forward per se I agree they provide presence, immediacy and dynamics in spades (undeniable qualities, to me), but it's worth noticing how their sound morphs depending on the recording; some, if not most of the more modern rock/pop recordings can sound flat, uninvolving and compressed (which they are), but put on (particularly older) jazz titles and classical music and the soundscape suddenly blooms into a vivid, colorful and very dynamic presentation. I've never heard the likes of violin, cello, piano, clarinet, saxophone etc. sound that authentic, full of life and presence. Dynamics, both micro and macro, isn't just a priority here; it's an outright necessity if one is to emulate the imprinting of live instrumental sound, as is truth of tone, sheer air displacement area, ease and overall coherency. Perhaps much of the controversy of horn speakers resides in their unsuccessful pairings, be that both with the associated equipment as with the music (i.e.: their recordings). Add to that the inertia of what audiophiles are used to hearing from mostly (smaller) direct radiating speakers, and horn equivalents can be found to sound "wrong" simply by virtue of having a different, more direct presentation.

Klipsch makes great speakers. Very dynamic, very accurate, something that audiophile speaker lacks severely.

Never heard the original "heritage" series (K-horns, Belle, La Scala, etc.), but based on my own speakers which are build around the design principles at least of the Belle Klipsch (mids and tweeters horn, drivers + x-overs are completely different; bass horns are very slightly "tweaked," and close to the original), I certainly agree on the above - insofar also we're dealing in both cases with fully horn-loaded speakers as a design basis and point of reference. I'd say the sound of horn here is denser, more present (yet wholly relaxed), and of with a wonderful ability to effortlessly convey complex material.

They ring a lot compared to beryllium drivers though. Which is both a pro and con.

Klipsch speakers "ringing" I'd wager has more to do with the horn construction and materials used than that used for the diaphragms, though the overall potential of the sound here originated is of course also influenced by the compression drivers as a whole. The original Klipsch horns sport relatively thin-metalled walls, and I imagine they can ring like bells at certain frequencies. I remember though reading of Art Dudleys ventures into modifying a pair of Altec Valencia's he had purchased, where he found damping the mids horns on the backside to have its flipside, so to speak, and robbing the horns of some of their sonic virtues - so much indeed that he found the tweak initiative here to be less productive overall. Same, in a sense, would apply to the man who build my speakers, and how he finds particle board (MDF) to sound "dead," and instead uses a particular kind of plywood to accommodate his preference. Though not beryllium vs. titanium, if this comparison even applies, the inclination towards killing most of the reverberating nature in materials, sometimes to counterproductive effect, is still the prevailing one. That being said, the "ringing a lot" of horns, just going by the reading of it, doesn't appeal to me. Some of JBL's "über"-models, like the K2's, now seem to me slightly on the pale and lack-and-substance side of sonics after being used to listening to horns made of stacked plywood (and a different compression driver). The JBL's here may sound "livelier" (some would say "splashier") in a sense, but to my ears quickly turns into a character less natural and too much "in the way." Oh well, there's livelier, and then there's "livelier"..

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.