I think they are fair points and you will always get best image quality with a prime lens.
I wouldn't worry about the macro lenses, they're very sharp and great for landscapes. The only complaint I've ever heard about using a macro lens as a "normal" prime was that they can be a little too sharp for portraiture.
But there is a big "but!...
and this was the reason I left the 4/3 system behind...
The real problem is the widest you can get (thats not fish eye) is 24mm and then with the 4/3 2x FOV multiplier... The 7-14 f/4 is you're only real extra wide angle option and it's painfully expensive! The 50mm is considerably sharper than the 35mm so then you're looking at a 100mm FOV which isn't landscape stuff.
You could consider the Sigma 10-20. I use one on my D90 (and it's actually weird looking through the viewfinder at 10mm - it's like the world has been squeezed into your camera) with good results but you're still only looking at 20mm at the widest.
And this brings you right back to the issue I had with 4/3. The ONLY really wide angle lens is the 7-14. And at over £1000 (currently £1,347 on
WEX) it's expensive. However, the whole range (7-14, 12-60 & 50-200) means that a sensible starter-pro lens selection is a little over £3,100 - thats
much cheaper than with Canon or Nikon (the Nikkor 70-200 f/2.8 blah blah is £2,000 alone).