Liverpool is strong this season, but you may be correct to say that they are not as strong as those seasons that Manchester City was very strong. But with the form every other club found themselves this season, Liverpool is very strong.
Consider it this way, that level of form that Manchester City was that you are expecting Liverpool to be cannot be achieved now. Remember that Manchester City won the league with 100 points but as at that time Liverpool also ended second position with 97 points which means both of them were in great form. So considering the total point of Manchester City now, it can be said that Liverpool is in Great form this season. They will not win the league with 100 points but they are better than all this season.
In recent time it has been Liverpool and Manchester city competing for the league title, they have relegated Manchester united and Chelsea that used to be the main competitors. I don't mention Arsenal Because they haven't shown any seriousness in their title race. Arsenal doesn't have any good squad to win the title, wining title depend on the maturity and winning mind set of the players. That is why you see Arsenal struggling every year for the title.
Liverpool is the strongest team in the league this season losing only one game out of 27 matches, only strong team can do such. Liverpool is taking advantage of the fact that Manchester city poor form this season, no team to heat the top with them, Nottingham tried but they are immature to push for the title, then the funny Arsenal has not chance. They always lose important game, Arsenal can't give liverpool heat for title, the strong this season Liverpoor will lift the title with ease.