The main problem I have with modern pens is the tendency in many of them to dry out too quickly in writing pauses and overnight. Parker Sonnet to 51 comparison, for example. Modern Pelikans and some other pens stay moist longer. This drying up issue is a real aggravation.I don't care about the weight of some modern pens. I get used to it. The Pelikan M640 Northern Lights is a pleasant pen to use. The nibs for this series are quite special.
The drying out of modern nibs did push me to use my 51s more and to use the Sonnets less. The Sheaffer Prelude, weight apart, dries up also, and the Imperial Touchdown pens are better. Even the Touchdown Cadet is a better pen for staying moist longer and not needing much to get started if dry. All the modern pens I have used are a nuisance about drying out except Montblanc and Pelikan. A very few Sonnets have been sort of passable. I prefer Sheaffer Touchdowns and Parker 51s, Pelikan M200/400 and Montblanc 144 and 146.
I almost think makers have forgotten how to make nib and feed work properly.