it really depends on the drivers involved.
a blend between a woofer and tweeter needs to "sum" to fill in the frequencies through the crossover range.
if both drivers are cut off sharply at the crossover frequency that missing summing could come off as recessed and lacking detail.
but there are exceptions to the rule, especially if the drivers have a rising response or extended response beyond the crossover.
if a driver has a natural acoustic roll-off at the crossover and you compound that with a steep crossover- e.g. 24 db per octave, then yes the system could sound dull and recessed.
a blend between a woofer and tweeter needs to "sum" to fill in the frequencies through the crossover range.
if both drivers are cut off sharply at the crossover frequency that missing summing could come off as recessed and lacking detail.
but there are exceptions to the rule, especially if the drivers have a rising response or extended response beyond the crossover.
if a driver has a natural acoustic roll-off at the crossover and you compound that with a steep crossover- e.g. 24 db per octave, then yes the system could sound dull and recessed.