Just was thinking about this subject - actors, actresses, directors and composers who did something great in the genre, and should have done more, but for whatever reason did not. Who makes your list?
My first thought after re-watching “The Mercenary” today is Tony Musante. He is absolutely terrific in a somewhat Milian-esque role as Paco. How did this guy not appear in a string of spaghetti westerns? Looking over his filmography, this was apparently the only one - what a shame.
To actors, a job is a job, and they don’t have the same nostalgic way of looking at these films, as we fans.
To be honest, many actors from the USA would have been a little embarrassed about appearing in a Euro Western - it wasn’t the benchmark for greatness. Eastwood and Van Cleef were the only ones who it helped internationally … and even when LVC returned to the States he wasn’t offered any decent work. 
Charles Bronson…maybe John Philip Law could’ve done more than one. Jean-Louis Trintignant could’ve done more I think…
Yes, it’s frustrating - though maybe not that all too surprising - to consider how little respect Eurowesterns were given in their heyday. Even Leone wasn’t afforded the critical reputation he deserved until years later. Of course some of these folks (Musante included) did appear in some other European films, crime dramas and such, but for whatever reason did not manage to make another western.
John Phillip Law is a great choice. He’s good, though maybe a bit hammy at times, in Death Rides a Horse. He could have probably played some Franco Nero-ish roles if he’d kept going.
Klaus Kinski was pretty hammy and he made several lol 
You are not wrong! Law’s performance is a specific type of hammy though, that is not what I’m used to in a spaghetti western. Obviously not talking about the revenge scenes, which he plays pretty straight and cold-blooded as one would hope. The rest of the time, he seems to me like he’s doing kind of a faux-John Wayne voice (I assume that’s him that did the dubbing in the English version) and has this kind of goofy, comedic presence. I still really like him in it though and it’s one of my favorite movies. I really wonder what he’d have done with a cool Eastwood-or-Nero type of bounty killer role, he certainly has the look and the intense stare when he wants.
Kinski was over the top in basically everything - always so intense. I love his movies with Werner Herzog. But few of his are small performances.
The main reason I revisit Death Rides a Horse these days is to chuckle at Law’s ADR. I find myself imitating it all the time 
Yeah, it’s not the best, in fact it’s awful. Note that I did say “maybe” lol I was grasping at straws.
He certainly looks good in the role. A fine Eastwood/Nero lookalike.
He even wears the exact same vest in Death Rides a Horse as Eastwood did in the Dollars trilogy.
Maurizio Merli immediately comes to mind.
I guess Merli’s rise to prominence as an actor came at a time when westerns were pretty much dead in Italy but I agree it would have been nice to see him do a few more. He had the look for it.
Henry Silva. Great face for a western.
I am in the middle of reading “Sergio Leone: something to do with death” and Charles Bronson turned down several offers on the dollars trilogy. I think James Coburn also turned down one of them - both could have made more SW’s.
I thought Brian Kelly who appeared in a did a darn good job in Shoot Gringo Shoot should have appeared in more. Some others include: Luigi Giuliani, Rik Van Nutter, Lang Jefferies, Merce Castro, Jim Garner, Richard Crenna and many others.
Robin Clarke, Anthony Ghidra, Anthony Steffen, Richard Wyler, Cameron Mitchell, Alex Cord…just to name a few.
Lang Jeffries is another that comes to mind. Sort of a Brett Halsey clone he had the look and was a decent actor. How about a thread on actors we wish had made a Spaghetti Western.
The guy pretty much disappeared off the face of the earth after Death Sentence. He went straight to American television and never got back onto the big screen after. Really sucks because he had some chops on him, and with the right director and film he could have gone someplace.
I’ll be honest, he did not seem interested in Requiem For a Gringo. At all. His ADR in that movie is just so atrocious.
Venantino Venantini.