Exactly WM, the fixed term parliament act is to stop governments just calling an election when they feel like it. Witness the Labour government of 1974, where Wilson led a minority government and shortly after, having had a budget beneficial to voters, went to the polls again in October with the aim of winning a majority. Contrast the SNP government of Salmond in Scotland where they governed for the full term as a minority government and were rewarded in the polls with a strong majority.
Personally I believe that were it not for certain die hard EUphiles, in all 3 main parties, who are willing to sink the EU negotiations in order to derail Brexit; May would not have had an election. The fact that she has called an election speaks of her strength. Not of her avarice or her willingness to play the system. This election is, first and foremost, to stop those who want to play the system from getting the UK a bad deal when we exit the EU.
For me there is nothing wrong in that. If she has had to reassess, after the calling of Brexit and the setting up of the parameters to negotiate Brexit and if calling the election is the right thing; based on that reassessment, then it speaks much of her character that she is doing what is right. Not the easy thing of leading the country into a mess because she honestly didn't believe, when she took over, that the country needed an election and it was just easier to go with what she said at the outset and not make the case for a different path.
It would be worthwhile to reflect on those who are trying to make much of this decision and what their motives are and were. Because almost every single person who has criticised this decision has attempted to cause problems for the negotiation of the UK's exit from the EU.
Notably the currency is up, significantly and the markets have followed. The only thing now holding the £ back from appreciating back to pre Brexit levels is the BOE who steadfastly refuse to follow their own guidelines. Even the IMF has had to roll back on the forecasts of UK growth in 2017, although they have gone all mealy mouthed over 2018.
The second that Tory EUphile members tried to derail triggering A50, this election became not only obvious, but necessary.