Technically speaking, Ottawa's goaltending after their horrendous first 11 games isn't so bad. Their team save percentage over the past 40 games is .903, with Ducks, Sharks and Coyotes all having worse goaltending over that span.
Despite what stats can say, goaltending hasn't been a problem at all, particularly after the 10 first games like you say (when they were "rusty" like everyone else). For people understanding goaltending (very few, almost have to be a goalie for that) and looking deeper, there's many reasons that can explain what happened but the problem was pretty much just ROAD GAMES. Their overall SV% at home for the season is 0.915 (9th in NHL)
It took a while to figure out how to defend at a NHL level on the road, there could have been many reasons/factors to explain that.
- poor personnel choices by GM/coach early that have been progressively fixed.
- No real training camp, many players not having played in 10+ months
- lot of roster turnover once again, took time to instill "hockey systems"
- team defense improved as the team got faster, much faster and young players also gained experience
So they have vastly improved defensively on the road (since April) to the point that it's not a problem anymore.
To summarize, the problem was team defense, not goaltending. Watching the games makes it obvious, how many glorious chances they were given up off bad turnovers or blown defensive coverage, and way too much time and space. Most NHLers with time and space will end up scoring often.