They were a good team that won 3 WS in 5 years, but were never great. Last year they had a spectacular first half of the season, seemingly on their way to another possible WS run. But they were one of the worst teams in BB during the second half of the season, although they came close to beating the Cubs in the playoffs.
This year is a continuation of last year's downward spiral, mode worse by the injury to Bumgarner. The only thing they do reasonably well is play defense.
As you noted, the pitching - both starting and bullpen - is terrible, and they play in a pitcher-friendly park.
They are perhaps the worst hitting team in the league. About half their games, they score 2 runs or less. Until recently they did not have a comeback victory when trailing after 7 innings. They regularly start a lineup with 3 or 4 players batting 240 or less. Since they are a team without much HR power, scoring runs is difficult.
Unfortunately they are playing mostly established players and probably aren't going to get better.