yes, there will be more errors and more putaway volleys to floating returns, but there will also be more return winners., more errors forced directly by the returns. also depends a lot on the quality of the SnVer, the rhythm the SnVer is in etc etc.
take the example of hewitt, his returning was that effective vs the SnVers though he didn't have great power. He'd rather play in the 90s than in the 2000s because the net rushers gave him more of a target and he could redirect the pace better.
Also - consistently SnVing on 2nd serves - was IMO not such a great tactic unless you had a very 2nd serve ala sampras , edberg , mac etc.
borg was one of the few who realized that and only occasionally SnVed on 2nd serve at Wimbledon.
Those servers that you mention were some of the all time greats. Throw rafter in there as well. I am not speaking of power servers. There were many that hit serves harder. Great servers dont use straight power. They use variety and disguise and have an uncanny ability to pick apart great returners.
Take Federer for instance. He is very good at blocking serves and has very good feel when doing this. A great server ala Rafter recognizes this as shown in there matches. What he does over and over is to stretch Federer out across the box and use variety and disguise to throw off Fed. Now Fed can blast too but not when he is stretched (nobody can). It also mutes the feel returns as he is contantly reaching high, low whatever. Body serves (which rafter used a lot) are pretty uncommon when they played.
Sampras was not quite as crafty as those other three but is flat serve and slider had so much wieght players had a lot of trouble with clean hits and in the end it well...he was Sampras and he probably had the most complete serve the game has ever seen.
In general though the big servers of the 90s were very good. Even the bombers had good variety and change ups. Now the game is missing that and servers very much use the second serve to get the point started from a nuetral or slightly better position. The great servers of old would try and hurt you with the second and then attack.
Its reallly kind of sad as the game has regressed. Tennis afficinados who love the game now would be absolutley thrilled watching matches from the early and late 90s. Wimbledon had a few dead years but outside of that it was fantastic. It was very much a time when players had to lift there game as apposed to now when its more about who doesnt choke.
Heres something to look at #1 players from the 90s
Lendl (rock solid all courter all surfaces)
Becker (Big dumb high risk boomer headcase streaky as heck)
Edberg (S&V effective all surfaces, poetry in motion)
Sampras (all courter fast court King)
Courier (Clay/ Hard court basline basher, physical monster)
Agassi (explosive, great returner,
Muster (Clay court monster with an iron will of a man on a mission)
Rios (short guy, genius, Mcenroe feel, all courter, all surfaces, craftey artist)
Kafelnikov (um? Great returner, all courter, dangerous)
Moya (incredible mover, explosive, huge forehand)
Rafter (S & V scrapper, Tactical as heck, Gutsy)
Hewitt (Prefontaine/Rocky, mean, scrappy, non intimidated, big match player)
Now take a close look at that list and you will see how amazing the contrast in styles were. Heck even the personalities were stark contrasts ranging from ellegant (edberg) to clownish (agassi) to intraverted (sampras) to all out I want to rip your throat out (Hewitt). It was a very unique time in proffessional tennis. I still cant believe they screwed up the sport as much as they have.
For more look at the point spread in the 90s. It was tight. Players were hungrier and were willing to take risk and put it all on the line. What more could you possibly want in sports.
*Some of those on my list might be a little off the 90s. When I say 90s I mean 89-2001ish.