2 main complaints to fetchlands, 1 minor one.

1: life loss. it is relevant in many cases.
2: it opens you up to stifle. the deck is only affected by the storm trigger. at that point you could play around stifle by ensuring you have a past in flames and can recast the storm card.
3: it could get pithing needled or spyglassed. (edge case, but still possible)

all of this needs to be considered for a very very small increase in odds. there's lots of information involved regarding how useful this is % wise. you'll just have to find them.