What if.....?

Depends if you mean spinning on its axis or rotation arbound the sun. Seasons are determined by our axial tilt and rotation around the sun. Not the direction we s[pin on our axis. thus it does NOT matter which direction the sun spins on its axis as far as the seasons go.

The seasons on our planet are more of a function of the way the earth tilts on it's axis

not the rotation. I think to change the direction of the earth's rotation would annihilate the biosphere

Earths season depend on its orbit around the sun and the angle of its tilt .It has nothing to do with the direction it rotates.

it'll still be the same, the seasons depend on the revolution of the earth, not the rotation

if the earth went the wrong way around the sun, nothing would change, autumn and spring are really the same thing for the earth, so if in midsummer you started going the other way round life would progress exactly the same, beacuse there would be no difference in the suns temperature to normal, it would go down after midsummer as normal. from midsummer, either way you go you are progressing to midwinter. from mid spring either way you go you are progressing toward mid autumn...etc...etc...etc...

We would still have 4 seasons.

Just about every place on earth would have a different climate and different weather than they have now though.

Same seasons, just backwards.