Is your rare worth more than the price of the pack or not?
It appears that this set shows the exact same price-pattern as a normal set, including the boost for higher MSRP.
Take your favorite standard legal (3.99 MSRP) set. Look through all of the rares - not mythics, just rares. Count how many are worth more than $4. (valuable commons/uncommons are worth noting, but are much harder to trade or sell at actual value at your typical trade or LGS in my experience).
Depending on set and metagame shifts/land cycles/pricing source, you will usually count between 6 and 12 rares, out of ~35-55 total rares. This is CONSTANT. Between 10% and 25% of rares in a set currently in standard are ever worth more than the price of the pack.
Choose a set and sort by your favorite price type. Using TCG Mid, here are my results. Rares worth more than $3 (slightly under MSRP):
•DTK - 10/53 rares, & 12/15 mythics (newest set, prices haven't stabilized yet)
•FRF - 2/35 rares, & 7/10 mythics
•KTK - 7/53 rares, & 5/15 mythics (fetchlands)
•M15 - 10/53 rares, & 8/15 mythics, 1 uncommon
•JOU - 4/35 rares, & 7/10 mythics
•BNG - 4/35 rares, & 6/10 mythics
•THS - 7/53 rares, & 10/15 mythics
The rest are bulk, or are at best a two dollar rare. The fact that some of the rares or mythics are worth two, five, or sixteen times the price of a pack doesn't matter - your chance of getting ANYTHING in the rare slot worth the price of the pack is, at best, around 25%. (In a typical set about half of the mythics are garbage, but it varies wildly depending on how WOTC allocated mythics in the set. Based on this I assume the 1/8th chance of a mythic has a 50/50 chance of being worth it, and can therefore ignore mythics for this type of price comparison.)
As of this writing (2015-05-08, 2:11 PM EST), TCGplayer mid sorted by price
http://magic.tcgplayer.com/db/search...Masters%202015 shows 9 rares in Modern Masters 2015 at or above MSRP of $10. (It also shows 13/15 mythics in this range, which is abnormally high - that's good!)
TL;DR including the higher MSRP, Modern Masters 2015 appears to follow the exact same value structure as any other booster release.
edit: for funzies, the (notably, out-of-print) Modern Masters, using a threshold of $6.99 has:
1 uncommon, 16 rares, 11/15 mythics
worth MSRP. Data are skewed by limited print run, and an out-of-print set. using 9.99 as MSRP for MMA gives 11 rares and those same 11 mythics.