Get wallet spammed a lot? Why not make the transaction meaningful. Up the requirement from 0.001 to 0.01 STEEM
You've seen lots of it. Spam messages in your wallet.
Not all of it is spam. Some of it is legitimate messages from blocktrades, your favorite bidbot, whatever.
But a lot of it is just spam. "Vote for my witness" or "Re-steem services", etc, etc.
This is advertising -- just like any other form of advertising -- the problem it is too cheap.
It is extra data to the blockchain, that often doesn't have to be there... and it's free to pump the blockchain with loads of this stuff... and it's only going to get worse.
Want to spam my wallet with a message? Ok, well tell you what...
Don't send me 0.001 STEEM --- instead, send me 0.01 STEEM -- this way, after reading 100 of these spam messages with the new price rate, at the very minimum, I'll end up with 1 full STEEM after reading 100 of them.
Right now, I have to read 1,000 spam messages in my wallet, just to get 1 full STEEM.
Steem is currently trading at around 75 cents as I write this... This means, you can send 1000 wallet spams out for for only $0.75 USD / or 75 pennies. :)
This is why the wallet spam problem is getting worse. Legitimate service messages are getting mixed up with anyone who has 75 cents to spam 1,000 of us.
If you don't see this problem getting worse.... then just wait. You're going to hate it even more in the future.
To lower wallet spam frequency now, and senseless transactions to the blockchain, implement a new rule that all wallet spam transfers "with a memo" must cost 0.01 STEEM
By the way, 
However, I won't be able to continue to be a witness long, without your vote. I'm running out of time. :( If you like what I write, and the concerns I bring up -- please consider intelliwitness for your vote.