Logos 10 Fundamentals or not?

Should I buy the Logos 10 Fundamentals, (I already have everything that is included there in my current subscriptions, so I am basically just buying the Logos 10 engine), or will it be better to get Logos 8 Pentecostal & Charismatic Bronze Legacy Library.

The Legacy Library will give me more resources, but I am not sure what is meant by "is offered without features and datasets".

If you buy a package where all of the content is included in your subscription, you won't see any change in Logos at all - it is as if you throw away your money (unless you stop your subscription: then you will fall back to the free engine [the engine itself is always free] without any of the paid features, datasets and the subscription-included books, or you will fall to the features, datasets and books included in Fundamentals - possibly less than you have now access to, but not much). With the Bronze Legacy Libray you will receive the books contained in there - nothing will change regarding your subscribed features, datasets etc. i.e. you won't acquire a permanent license for your subscribed features and you will not get additional features.  

Logos 10 comes with many new features, but the way I understand it, not much of that is included with Fundamentals. One need to buy the more expensive packages to benefit from the new features?

Since you already subscribe (sorry, I'm not familar with the detailed content of a Logos Explore subscription), you probably have access to some, but not all of Logos 10's features. Not sure whether there is a detailed comparison page somewhere. If you were to upgrade your subscription to Verbum Now (9.99 / Month, all of the Features) or a tier of Faithlife Connect (Starter 8.99 giving some, Essentials 14.99 all of the Features with a number of additional perks) you could obtain those features you need at what might be a more reasonable price.