Kevin Goldstein does a nice job of explaining the service time manipulation issues in a fair and balanced way:

It all points to a system that is broken; the service time game is at fault more than its players. 

FanGraphs.com

Goldstein finishes with suggestions for setting the start of service time to when a player signs his first contract, or by a certain age. While those are fine, one point that is missed why there is a reserve period in the first place.

When free agency came into being, two issues came together to set service time. The players union wanted to limit the number of free agents to keep supply low and contracts high. The teams wanted to recoup the investment made to develop the player in the minors.

How long does that take? A Baseball Prospectus article from 2013 suggests that the cost of developing a good, per-arbitration player is about 1/2 the value of a free agent WAR. So a two-WAR player would pay for himself and provide the team with residual value. So why not set free agency at three years or four WAR, whichever comes later. If a team develops a four-WAR a year player or better, they get to keep him for three years, then he hits the free agent market. He will get paid at the height of his ability. If they develop a one-WAR a year player, they get to keep him for four years. While a free agent payday will be nice for that player, teams are unlikely to be falling all over themselves to sign him. Maybe he does a long-term deal because he likes the team and the team likes him

Basically, this puts money in the pockets of the best players early. That what the union should strive to achieve in this negotiation.

Or just do universal free agency and do away with all the drafts and service time rules and arbitration battles.