Sounds like not much hassle owning land but you need to be careful about:
a). Good title
b). Planning permission - is it really zoned as per the agent says or will their be complications either getting planning permission or with the existing planning permission
c). Does it have electricity, water, sewage facilities nearby.
d). Any plans for future rezoning in the area that improve or reduce the value.
e). Was a survey of the land done recently to see what the ground is like and what can be built on it. I've seen cases where the cost of the project is much more expensive due to the foundations required.
f). Is there a resale value on the land and could you sell for at least the same price the next day after buying...
Anyway, I'm sure you've considered the list above and many more items.