Good= Shawn was simply one of the best of all time. Incredibly talented in the ring, HBK could wrestle, he could fly and he was incredibly innovative. He was in alot of "firsts" in the WWE from the ladder matches to the elimination chamber to the Hell In A Cell matches. Shawn could always be relied upon to put on a show-stealing performance night after night, right up until his retirement, which is some going.
One of the best "sellers" of all time, HBK could draw you in and make you believe that he really was in agony, before kipping up and nailing someone with the Sweet Chin Music, one of the greatest and most iconic finishing moves of all time. Even after coming from from what everyone (Shawn included) was a career-ending back injury, HBK continued to steal the show every night, and put some incredible matches with so many guys (Triple H, Chris Jericho, Ric Flair in his retirement match, Undertaker at WM spring to mind).
He was part of the reveultionary faction D-Generation X, and was one of the catalysts of bringing "Attitude" to the WWE. Controversial, x-rated, hilarious, the original version of DX was brilliant, and with Shawn as his mentor, Triple H was able to grow as a perfomer and take over the faction after Shawn's retirement. Without HBK, I do not think Triple H would be where he is today.
After having serious issues with addiction for a long time, Shawn was able to get better, and after finding the Lord, turned his life around. He is a credit to what someone can achieve when they put their mind to it. He now does alot of work for the church and is a gret example of a family man.
The Bad= As mentioned, Shawn was not the biggest draw as champion, which is a black mark against him being the greatest of all time. As as in-ring perfomer he is the best, but if you dont make the company money then there is a problem. Also, as he is not the biggest, there is the believability factor in him beating guys much larger, although HBK (along with Bret) was one of the main guys in breaking down to a degree the "big guy beats small guy" mentality after the steroid trials in the 90's.
Also, his lack of title reigns after his retirement doesnt look good. Although willingly giving up the title opportunity due to him needing to go to church the morning after, I do think the WWE should have accomodated Shawn's religion and given him more championship reigns after he returned to the company. Yes, he had the short reign after winning the first Elimination Chamber match, but HBK as champion would have given the belt so much credibility after it had bounced around from wrestler to wrestler in the last few years. Maybe Shawn could have retired after losing the title to Undertaker at WM this year???
The Ugly= The backstage politics that marred Shawns early WWE career have to be mentioned here. Notoriously difficult to deal with as a young guy, even more so after the formation of the backstage clique, Shawn earned a reputation as a trouble maker and was incredibly arrogant. However, in later years this changed and HBK would do the job whenever required, which can be seen in the fact that he lost many championship matches after returning to the WWE and was happy to go out on his back.
The Montreal Screwjob. Where to begin? It is very unlikely that we will ever know the entire story, but Shawns role in it (whether he was in the right or in the wrong, and its probably a bit of both) does leave a sour taste in the mouth. He will always be a hate figure in Canada for whatever he did in Montreal, and it was sad that 2 of the greatest of all time- Bret Hart and Shawn Micahels, could no co-exist, as they made put on great matches together.
It is well known that Shawn had a severe drug addiction for years, which led to family and fellow wrestlers becoming worried about him. He would just go out and get wasted every night, as he admits himself and it nearly cost him his marriage. However, after finding God and help from family and friends (HHH and Kevin Nash did alot here), HBK was able to kick the habit and com back better than ever.