If the bike fits your body and purpose, if something about it stirs your soul, repainting and rebuilding can be very rewarding.
If balancing this project against a new bike consider:
A new bike looses one half it's purchase price between the dealer's door and the street. Old bike values hold steady or increase with time.
What's "hot" this year is old news next year, which can be disappointing. Interest in old bikes is growing.
Old frames have nostalgia and rarity going for them and in many cases a level of craftsmanship which is disappearing.
Until recently, most bicycles could last a lifetime given reasonable care and maintenance. Contemporary bikes often have complex components for which replacement parts will not be available, are made of super light materials with limited life-span and no possibility of repair.
We see people every day refinishing their old frames after purchasing a new one because they prefer old frames ride. Most new frames are aluminum. Any flexing causes fatigue in aluminum, and aluminum's failure mode is dangerous, so manufacturers have overbuilt to eliminate flex. Modern rims and tires also contribute to a harsher ride. Oversized tubes have proven to be a popular selling feature, even when they have not been shown to improve the bikes "feel". You already know that you like the ride of your existing bike. There is no guarantee that you will like the handling characteristics of a new one.
Typically we can do a "better than new" refinish on most top quality frames for less than half the new purchase price of a replacement.
If your frame is steel, you should know that steel is the most fatigue resistant, repairable and adaptable of frame materials. Braze-on changes, hub space changes, even tube replacements after severe crashes are feasible. It is not impossible for a good frame to last a lifetime.