I find conventional Western notation works quite well for communicating notes, rhythms, and basic expression, but it breaks down pretty quickly once you move beyond that. E.g. a lot of the common techniques on electric guitar (bends, palm muting, tremolo/whammy bar stuff, pick slides, slap/thumping, pinch harmonics, raking) don't really have a convenient notational shorthand. That's without even mentioning synthesizers (how do you notate 'gradually increase the filter cutoff here'?) and DAWs, samplers, drum machines. But it's definitely a hard problem: the more information you try to shove into a notational system, the harder it gets for people to keep track of what everything means. Plus you just start running out of easily distinguishable symbols at some point.

I'm not sure what you are talking about wrt guitar and standard notation. Finger (PIMA) indication, staccato/legato, vibrato, tremolo, slurs, hammer, pulls, etc...it's all there. I don't see as much notation around hammer/pull as a classical player, but pick up a classical guitar music book sometime...you'll find that everything (guitar-related) you mentioned needing to be included, is already included.

Not sure what you consider convenient, but I’ve never had a problem reading electric guitar notation. It’s handled the same way we notate extended technique for other instruments - a combination of text above the staff, and squiggly lines on it :)

What?! I'm surprised those are the things you complain about regarding guitar sheet music.

The only real problem is guitar always has several different ways to play the same notes all over the neck and instrument tuning isn't always specified either.

Standard tuning may not work and tabs sometimes aren't there alongside the staff. If you're trying to sight read, you'll guess alright for a while until you are suddenly forced to make heroic leaps to the other end of the neck or painfully contort your fingers just so you don't miss a beat.