Futility edit 1

[Emz]

The Drips tick and tap on my windshield (Drops may work better as ronsaik pointed out)
as obedient wipers erase all impact
of rain drops' final act of expression I really like this stanza. My above suggestions work with plural, but I wonder if it may be better talking about one single rain drop and have that follow through the whole poem. 

Streaming down my glass ending in a lifeless puddle

Why should rain wage battles
against gravity,
rising in a cloud to glimpse the Sun
only to crash back to murk?

I wonder if it may sound better like this:

A drop taps on my windshield
as obedient wipers erase all impact
of a rain drop's final act of expression.

Streaming down my glass
into a lifeless puddle
where other drops have fallen.

Why should rain wage battles

against gravity,
rising in a cloud to glimpse the Sun
only to crash back to murk?

I don't mean to do an entire rewrite for you or anything; I just had a couple of ideas and I hope there is something from this you may like.  

Overall, I enjoyed your poem

Emma