Maybe now, but not before the nerf there pal.
Even before the nerf they were the least viable sentinel spec in competitive ranked games, ask anyone who plays ranked competitively. It doesn't fit into the meta of calling a target and bursting them down, and good healers cleanse dots. And it's obviously good 1v1 but it can't off-node guard without stealth and will lose to a good scoundrel or shadow when they get the stealth opener. It's great for 1v2ing bads which might be their justification for the nerf, but doesn't really have a place in competitive play right now. It's sad- it's probably my favorite and best spec. Now I'm always either focus or combat in rateds depending on what the team needs and on the warzone that pops.