Let's start off by saying the Tigers would like to sign Scherzer, and Max would like to sign with the Tigers. But we must remember it is also a business for both the team and player.
Considering the going rate of quality pitching, a $25 Mil. per year for 5 years seems where to go for both. Now let's see why that amount and not less and not more.
Max can demand this salary because there is no doubt he has become one of the elite power pitchers in the MLB. With great stuff and control, and stats to back it up. Better than all #2 starters and most #1 starters in the league.
Why not more like a Verlander/Kershaw contract? First one of the extra perks you pay for in a #1 starter is IP and CG (so you can rest a tired or suspect bullpen). Verlander has 6 career complete games, Max has 0. Verlander has more innings pitched, including 2013, 218.1 -vs- Max's 214.1. Max is also the pitcher who benefits from more run support than any other pitcher, look at A. Sanchez who had the lowest ERA in the league and plays on the same team and compare there W-L records.
Let's compare Max to a 35 year old pitcher (which Max would be in 5 years) that makes $25 Mil. That pitcher would be Cliff Lee. They both have won a Cy Young, both are on a team where people disagree who is #1 and #2 starters ( Verlander/ Scherzer-Hamels /Lee), could go either way on either team. Although I believe Verlander is the elite of the elite, HOF bound. Max has a better SO avg. 178.2 per year -vs - Lee 146 per year, Verlander is 185.2 per year. Max is a little better in wins with 12.2 per year- vs- Lee 11.6 per year, Verlander is 15.2. Lee has a advantage in CG with 28 to Max's 0. Lee has a edge in IP 173.1 per year to Max's 170.0 per year, Verlander is at 197.0. Lee hase a better career WHIP 1.19 and ERA 3.51 -vs- Max's 1.23 and 3.67, Verlander has a 1.19 WHIP and lower 3.41 ERA.
I am sure the Tigers would like to keep there 3 headed monster Verlander, Scherzer, and Sanchez (compare to Maddux, Glavine, and Smoltz) together, with a breakout Porcello, and a up and coming Smyly. The only other team that is headed in that direction is Seattle with Hernadez, Iwakuma, and a up and coming Walker. Some may say Washington, but to me that is a bunch of good quality pitchers who have had one great individual year each, separately