Russia is another good choice. Its not hard to make peace with Turkey at the start or keep out of a war with Sweden. This mainly leaves you to watch Crimean Khanate, which you can defeat easily at start, and Dagestan and Georgia which is not hard to deal with either. Russia allows you to slowly build up and turtle all you want even with v1.3 patch I have found. Russia's economy isnt high though and you do need to build up the farms, factories, and its cities but this also fits in with turtling pretty well. Then once you are ready you only have two directions to attack basically. West and/or South. Just make peace with Turkey and stay friendly to them and all you have to do is move west. Turkey isnt a powerhouse in AI hands so if you do get into a war with them just take them one region at a time. Rarely have I seen AI Turkey invade Russia and then it'll only be a small raiding party through Moldavia.

Russia doesnt allow for much naval fighting early on though because you need to take St.Petersburg and the port near it before you can get access to the Baltic and ships. You can turtle up your economy and land forces however for a while before going at Sweden and St. Petersburg.