Obviously I didn't ignore the baselines. I didn't compare the 88% to the 44% of games the Cavs won, I compared the increase (61% to 88% compared to 25% to 44%). Rondo's increase was about 50% higher than Irving's. Over an entire season, Irving's scoring is worth about 15 extra win, Rondo's triple doubles would be worth about 22 wins.
No, I'm sorry, this is patently misleading.
Over the course of a season, Rondo will have ~4 triple-doubles, and Irving will have ~25 25+ point games (based on how frequently both of these have occurred over their careers so far).
So Irving's impact is clearly stronger than Rondo's -- Rondo's triple-doubles will be worth about 1 extra win, and Irving's 25+ games will be worth ~5 wins.