Assessing organizational maturity (i) is very important when deciding whether to introduce a test tool, as implementing a tool in an immature test organization with poor processes is unlikely to produce any benefits.
A quick return on the initial investment (ii) in a test tool is rare.
Having a requirement that a tool should be easy to use for untrained and unskilled testers (iii) is generally a false hope. This is comparable with expecting someone who has never driven a car to be able to drive safely and effectively.
Agreeing requirements before evaluating tools (iv) is essential. Not to do so would be comparable with building and testing a system without requirements.
In conclusion, (i) and (iv) are good principles to follow when introducing a tool and (ii) and (iii) are not.