I suppose one reason why a comparison of Suarez's 11/12 season with Firmino this season is that it's probably the season where they would be the most positionally similar. Suarez played with Carroll in 11/12, but was more or less the main striker thereafter.
I've done a comparison of the league stats to see how they've looked in terms of the numbers.
In terms of stats (league only): Suarez 11/12 vs Firmino 15/16
Suarez, 31 games, 11 goals + 3 assists. Firmino, 25 games, 8 goals + 7 assists.
Suarez, 4.1 shots per game. Firmino, 1.9 shots per game (this is probably up by quite a bit post-Rodgers)**
Suarez, 2 key passes per game. Firmino, 1.6 key passes per game
Suarez, 2.4 dribbles per game, Firmino, 1.5 dribbles per game
Suarez, 2.2 offsides per game, Firmino, 0.5 offsides per game
Suarez, 1.1 tackles per game, Firmino, 2.2 tackles per game
Suarez, 2.2 times dispossessed per game, Firmino, 2.2 times dispossessed per game
So from what I can see from the stats and memory, Suarez 11/12 vs Firmino 15/16:
Similarities:
Both like a dribble (although Firmino's dribbling is way down from his Hoffenheim dribbling - I understand the Bundesliga has a much higher rate of dribbling generally, but Firmino's dribbling has gone down by 2/3 per game, which surely goes beyond the German league factor)
Both like to contribute defensively (although Firmino gets involved even more than Suarez)
Both have a range of finishes
Differences:
Suarez sometimes played off the shoulder - Firmino very very rarely does, even when he's the furthest forward - possibly reflected by Suarez being offside four times as much as Firmino
Suarez gets into good heading positions and scores a few headed goals - Firmino does not
Suarez drives into the area with the ball at his feet. while looking to play - Firmino does not
Firmino tackles even more than Suarez - quite a lot more
Suarez shoots way more than Firmino - and he's always done so, even when he was at Ajax and Firmino was at Hoffenheim. Firmino's shot output was a lot higher at Hoffenheim, and it's been a bit higher under Klopp - see below. This indicates that he has a higher shot potential than he's showed in the league so far. It's still far off Suarez numbers though.
**
Firmino's shots per game for Liverpool:
2.1 shots per game in the league under Klopp
2.6 shots per game in the Europa League
4.1 shots per game in the League Cup