That might be true for the whole party. I have no whole party experience with DW. Also, you are taking Lost in the shadows stealth upgrade and IMO, it is somewhat easier to handle but suboptimal compared to Clinging shadows as you lose considerable portion of the damage boost. That means that there is a need to respec.
That is correct. I always respec after getting the specialization. I respec a few times during a full play through. JoH requires a slightly different load-out than Descent, for example, particularly for mages.
When you are talking about solo experience, it's best to make that clear up front. That's the unusual case. Most people play with a party. And BigBrolly said "in a full party".
Re: Finesse
There are a handful of situations where a DW shouldn't just charge in under Stealth.
Some high damage bosses have the Perceptive trait, which means they see right through your Stealth and target you. Dragons have this trait, for example. In such cases, let a tank Taunt the target to keep aggro away from you.
Another situation is when a high damage boss, like the Envy Demon, has an AoE attack that centers on them. It's designed to punish melee characters. Usually they have a pattern or a wind-up you can memorize and evade just before the attack happens.
Finally, since you will be in Stealth most of the time, any of you party that is set to "Follow Controlled" AI will get confused, because, they can't see you either! Best to set your tank to follow "self" (e.g., if you are using Cassandra, set her AI to Follow Cassandra") and then set the rest of the party to follow the tank. Nobody should be to follow you or follow controlled if you always control your rogue.