Tim Hardaway's defense has shown substantial improvement over the years. Check the above links for further details but to summarize:

in 2013-2014, in 80 games, on 7.1 attempts per game, opponents shot 5.3% better than their season average (49.0% vs. 43.8%)
in 2014-2015, in 68 games, on 8.0 attempts per game, opponents shot 4.4% better than their season average (48.0% vs. 43.6%)
in 2015-2016, in 51 games, on 5.6 attempts per game, opponents shot 7.3% worse than their season average (36.0% vs. 43.3%)
in 2016-2017, in 77 games, on 8.8 attempts per game, opponents shot 3.5% worse than their season average (40.7% vs. 44.2%)

per basketball reference, Timmy's defensive rating has improved from his rookie year (114) to 114 (Yr 2) to 106 (Yr 3) to 109 in 2016-17.

also his stats per 36 minutes are comparable to Victor Olapido and Evan Fournier.

some whilst I think his contract is an 10% overpay, a case can be made that it's close to fair value.

http://www.82games.com/1617/16ATL6.HTM

He played better for them than I originally thought. I think they match

Now he's got Melo giving him help defense and a coach like Hornaceck.

This signing has disaster written all over it.