You can get a Pr 6 or 7 from just backlinks, So your not nessecerily a expert because of your PR Personally here is how I would describe a SEO Expert Somebody who is able to choose a niche and keywords() and rank particually high/First on SERP continuously. Short but Simple!
I suppose it's all relative to your own personal views of an "expert". Although I'm new this forum as a poster (not as a viewer), I've seen some self professed SEO experts showing top rankings for particular keywords. Unfortunately, those keywords were low search/ low competition words that most any decent SEO person could rank for. IMHO, I would classify an SEO expert as those folks who can consistently rank and convert traffic in the top 10 on Google for ultra competitive keywords. I include the "and convert" part as conversion has to play a role in one's effectiveness within SEO. Getting a boatload of targeted traffic through SEO is great, but you haven't really succeeded if you can't convert it to your end goal (sales, leads, opt-ins, etc.).
according to my view, SEO expert is persons who knows and can implement all legal way to improve site ranking in search engines for keywords which sites want be targeted.
To be an expert in any field, takes required knowledge to be grasped first. Then you need to apply those on real time basis. If your clients are satisfied with your effort, then you are right on the track. Your friends, colleagueus and clients should claim you an 'Expert' if target is achieved - by far which is a continuous process
for seo expert is the one who have a wide experience of seo in different category of websites, can solve all website problems, can dominate search engines especially google by paid links and organic search and can drive traffics and sales to the website.