in certain IT fields such as service desk (helpdesk), if you don't hop, the only thing you can do is sit there waiting boss giving you chances, which depends on various other parameters including non-performance related (office politics)

for young people under the age of 30, it is encouraged to hop between jobs at reasonable interval, time is more precious than money at this point in life. If you find that your boss can't provide the opportunities you want, and that you have reached saturation in your learned stuff, then it's time to move on.

gain different exposure, learn both technical and management skills, make it as rojak as possible, is one of the path leading to becoming a manager.

I somewhat feel that, the more specialized you are in certain field, the harder it will be for you to start your own business, should you want to be your own boss one day

Would'nt it look unhealthy when the employer view ur resume? I am considering a job hop too but I m  in my current job for only one year (previous job less than 2 years)..My concern is how should I answer in a persuasive way when the interviewer ask me "why do u want to look for a newjob, you've been in ur current job for only 1 year?"

How would you answer that? If i say for better career prospect/ career progression, it might not be convincing to the interviewer as he might think one year is too short to have learned all the stuffs...