For the past few weeks, ever since the new hero Orisa came out and beyond with new patch updates and features, Overwatch players have been complaining on both PC and console that it's becoming increasingly difficult for them to achieve a higher SR (skill ranking) with support players like Mercy, Zenyatta, Ana, Symmetra, and Lúcio. Speaking for myself as a Mercy player, I too have been running into the same issues, even with my gun out and helping take down enemies when I'm not healing. And as a result, you may be noticing that more Season 4 matches across the board have been seeing fewer healers and more DPS-focused heroes.
Blizzard, not one to shy away from getting into it on their own forums, addressed the matter yesterday when Overwatch's principal designer Scott Mercer took the matter on himself and explained that what's going on isn't as simple as you may assume.
"As part of the 1.9 Orisa patch, we made a change to how assist scoring was handled to address what we honestly considered to be a bug. Players were getting full assist credit even if the player being assisted did very little to the target. This change, along with other more significant balance changes in the patch, meant that we needed to recalibrate the tuning for the systems that calculate a player's contribution to the match. This was performed for all heroes several weeks ago, and we've already recalibrated once more after the recent 1.10 patch."
Mercer also addressed the "On Fire" situation in greater detail, but the basic message to fans is that they believe the system is fine the way it is, and in actuality, was a problem that they fixed to make things much more balanced. The majority of responses on the forum seemed positive and gives new strategy toward how you play as a healer. Now we just need to wait for the next patch to arrive for people to complain again.