I was thinking of starting an app review site, i was just wondering if it is too competitive? has this niche already been dominated?
I would say no, it's always based on quality of content and if you can provide the information with better quality you will win the market share. It's just a lot of work and will take a long time investment.
I agree too, you need review app which popular and having more demand and make sure you cover as much as comparision features possible which would help end user to make final decesion. Though it requires quality design and look.
There's competition in every niche so you'll be sure to find this in the app review niche. I suggest you do your market research and find out your target market so that you can map out your site as well as what keywords you'll target prior to building your website. Hope that helps. Have a good day!
I suppose that in case you've got a unique point of view towards the app review process, perhaps, and if you pay enough attention to the design of your blog, you might try to enter the competitive niche.