I think you're incorrectly evaluating receiver talent if you think paying him BELOW what Eric Decker got from the Jets would be a realistic scenario...
The Jets overpaid for Decker because they are desperate for any kind of receiver talent (see: Santonio Holmes). They also overpaid for Decker because he put up those stats with Peyton Manning, one of the greatest QBs of all time, at the helm of that offense. Geno Smith is not Peyton Manning. Not to mention, Decker never operated as a #1 receiver at any time while playing with Peyton Manning. Demaryius Thomas filled that role, and let's not forget about Wes Welker and Julius Thomas helping Decker see tons of single coverage.
Not to mention, you don't seem to realize how rare talented, monolithic (6'5") receivers are in the NFL. Decker is 6'3", not 6'5". That is a SIGNIFICANT difference in height. Why? If a corner is 5-10"-6'0", that means Decker has a 3-5 inch height advantage. Miles Ali at 6'5" would have a 5-7 inch height advantage. Every. Time.
There are only a handful of talented 6'5" veteran WRs. Calvin Johnson and Vincent Jackson sit atop that short list.
Since Miles Ali only has 85 SPD at 6'5", he's much more closely compared to Vincent Jackson. Ali compensates for the 85 SPD with 94 ACC (at 6'5", that's RARE), and a JMP stat suitable for an Elite WR: 93.
Vincent Jackson's contract history requires a little extra explanation. He was drafted in the 2nd Round and signed a 4-year rookie contract. After those 4 years were up, he became a Restricted Free Agent. The old CBA at the time had an uppermost tender level that the new CBA abolished. The old CBA's highest tier tender was a 1st+3rd Round pick as compensation. The new (current) CBA's highest tier is now just a 1st. So, when VJax became a Restricted Free Agent after his rookie contract expired, he got slapped with the highest tier tender of the old CBA, at $3.268 million. He balked at that treatment and staged a holdout in 2010 that lasted the majority of the season. He signed the tender one day earlier than necessary simply to acrue the extra year of seasons played for his NFL career. That should have allowed him to hit unrestricted free agency in 2011. However, during that offseason, the new CBA was put together, and an unfortunate side effect of that was that certain players like VJax managed to get stuck as a restricted free agent for an extra year. VJax was franchise tagged just before the NFL Lockout for the 2011 season, which paid him $11.4 million that year. When he finally reached free agency in 2012, he turned the Chargers down when they finally offered him a long-term deal in the neighborhood of $10-11 million per season. He signed with the Bucs on a 5-year deal for $55,555,555.55.
That should illustrate how rare talented 6'5" receivers are in the NFL, and what lengths teams will go to in order to maintain control of them. For two years the Chargers wouldn't let him out of their clutches, even though he was clearly discontent with the whole situation, to the point of holding out for almost an entire season. They would have franchise tagged him again in 2012 if the CBA hadn't stipulated that if a player is franchise tagged twice, his salary for that second time being tagged is a 44% raise from the previous year. It would have cost the Chargers around $16 million to franchise tag him for a 2nd time.
http://www.nfl.com/player/vincentjac...506400/profile
And all those contract issues centered on a receiver who had achieved just two 1,000+ yard seasons in his career. His season best at the time was 1,167 receiving yards. He also had NEVER reached double-digit touchdowns in his career in a single season. A guy like Miles Ali, in your example, having nailed the 1,200 mark 3-4 times, plus 13 TDs per season would have teams fighting over him tooth and nail. To be honest, the WR franchise tag should pretty much be your starting point of his average annual salary: in the neighborhood of $12-12.5 million per season, realistically.
Also, when we're classifying receivers based on body-type, weight is almost as important a factor as height. Larger receivers (weight) are harder to bring down and tend to be able to absorb greater hits, making them more valuable when making contested catches in traffic (over the middle), or jump balls. Eric Decker is not only just 6'3", but he's just 218 lbs. Vincent Jackson is 6'5" / 230+ lbs. It's a rare body type for Elite receivers.
Decker is more comparable to 6'3" / 217 lbs Jordy Nelson.
After having played fantasy football extremely in-depth for the last 5 years, I'm very familiar with player contracts and height/weight statistics.