Lewis is a better short yardage/goalline RB than Gillislee & Blount.
I can't agree with this type of blanket, generalized comparison.
Gillislee and Lewis have different running skills and abilities, different ways of getting yardage on the ground. One skill set may be more optimal than the other depending on the game situation and on the opposing defense - their strengths/weaknesses, their scheme, their tendencies - and on how the Pats offense is setting them up to be exploited.
OTOH, the argument that Lewis is always a threat to catch a pass out of the backfield (whereas Gillislee is not) is a fairly valid one.
Over the course of Gillislee's 29 NFL game appearances, he's seen a total of 18 targets and caught 15 of them for 79 yards (5.3 ypc, longest of 18). In just the 13 games since he came back last season, Lewis has caught 24 of 31 targets for 136 yards (5.7 ypc, longest of 16). However, none of this means that Gillislee CAN'T catch passes out of the backfield. It just means that we don't expect him to. Perhaps certain opposing defenders don't expect him to, either. Advantage: Patriots.
Anyway, to say with certainty that one is "better" than the other is just too apples-and-oranges for me.
BTW -
Lewis has had four rushing TDs in his time with the Pats:
2015:
... from 6 yards out on 2nd & 3, Q1 v. BUF (week-2)
... from 8 yards out on 2nd & 8, Q1 v. JAX (week-3)
2017:
... from 8 yards out on 1st & 8, Q4 v. CAR
... from 1 yard on 1st & 1, Q2 v. NYJ last Sunday.
Gillislee's four TD runs for the Pats have been 2yds, 2yds, 1 yd, 2yds (also all on 1st or 2nd down). Six of his 8 scores for BUF in 2016 came from 3yds out or less (plus another from 5 yds).
In 2016, Blount scored 11 of his 18 TDs from the 1-yard-line, plus one from the 3, plus another from the 1 against PIT in the playoffs.